United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/540/AR-92/010
December 1992
oEPA
Silicate Technology
Corporation's Solidification/
Stabilization Technology for
Organic and Inorganic
Contaminants in Soils
Applications Analysis Report
•.vr" - +\»"
SUPERFUNO INNOVATIVE
TECHNOLOGY EVALUATION
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EPA/540/AR-92/010
December 1992
Cr-
SILICATE TECHNOLOGY CORPORATION'S
SOLIDIFICATION/STABILIZATION TECHNOLOGY
FOR ORGANIC AND INORGANIC CONTAMINANTS IN SOILS
APPLICATIONS ANALYSIS REPORT
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, 12th Floor
Chicago, IL 60604-3590
Risk Reduction Engineering Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
Printed on Recycled Paper
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Notice
The information in this document has been funded by the U.S.
Environmental Protection Agency under Contract Nos. 68-03-3484
and 68-CO-0047, and the Superfund Innovative Technology
Evaluation (SITE) program. This document has been subjected to the
Agency's peer review and administrative review and it has been
approved for publication as a U.S. EPA document. Mention of trade
names or commercial products does not constitute an endorsement or
recommendation for use.
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Foreword
The Superfund Innovative Technology Evaluation (SITE) program was authorized by
the 1986 Superfund Amendments and Reauthorization Act (SARA). The program is a joint
effort between EPA'sOfficeofResearchandDevelopment(ORD)andOfficeofSoKdWaste
and Emergency Response (OSWER). The purpose of the program is to assist the develop-
ment of hazardous waste treatment technologies necessary to implement new cleanup
standards that require greater reliance on permanent remedies. This is accomplished through
technology demonstrations that are designed to provide engineering and cost data on selected
technologies.
This project was a field demonstration under the SITE program and was designed to
analyze the Silicate Technology Corporation solidification/stabilization technology. The
technology demonstration took place at a lumber treating facility in Selma, California. The
demonstration effort was directed to obtain information on the performance and cost of the
technology and to assess its use at this and other uncontrolled hazardous waste sites.
Documentation consists of two reports: (1) a Technology Evaluation Report that describes
the field activities and laboratory results; and (2) this Applications Analysis Report that
provides an interpretation of the data and discusses the potential applicability of the
technology.
A limited number of copies of this report will be available at no charge from EPA's
Center for Environmental Research Information, 26 Martin Luther King Drive, Cincinnati,
Ohio45268. Requests shouldinclude the EPA documentnumber found on the report's cover.
When this limited supply is exhausted, additional copies can be purchased from the National
Technical Information Service, Springfield, Virginia 22161, (703) 487-4650. Reference
copies will be available at EPA libraries in the Hazardous Waste Collection.
E. Timothy Oppelt, Director
Risk Reduction Engineering Laboratory
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Abstract
This Applications Analysis Report evaluates the
solidification/stabilization treatment process of Silicate Technology
Corporation (STC) for the on-site treatment of hazardous waste. The
STC immobilization technology utilizes a proprietary product (FMS
Silicate) to chemically stabilize and microencapsulate both organic and
inorganic wastes, and to physically solidify contaminated soils.
The STC treatment technology demonstration was conducted
under EPA's Superfund Innovative Technology Evaluation (SITE)
Program in November, 1990, at the Selma Pressure Treating (SPT)
wood preserving site in Selma, California. The SPT site was
contaminated with both organics, predominantly pentachlorophenol
(PCP), and inorganics, mainly arsenic, chromium, and copper.
Extensive sampling and analyses were performed on the waste both
before and after treatment to compare physical, chemical, and
leaching characteristics of raw and treated wastes. STC's contami-
nated soil treatment process was evaluated based on contaminant
mobility, measured by numerous leaching tests; structural integrity of
the solidified material, measured by physical and engineering tests and
morphological examinations; and economic analysis, using cost
information supplied by STC and supplemented by information
generated during the demonstration. This report summarizes the
results of the SITE demonstration, the vendor's design and test data,
and other laboratory and field applications of the technology. It
discusses the advantages, disadvantages, and limitations, as well as
estimated costs of the technology.
Conclusions resulting from this SITE demonstration evaluation
are that (1) the STC process chemically stabilized contaminated soils
containing both inorganic and semivolatile organic contaminants; (2)
PCP concentrations were reduced by 91 to 97 percent as determined
by total waste analysis (SW-846, Method 8270); (3) arsenic and copper
were immobilized based on various leach-test criteria; (4) chromium
concentrations were very low prior to and after treatment, but showed
a slight to moderate increase in teachability after treatment; (5) PCP
concentrations remained above California state regulatory threshold
levels after treatment, and metal contamination in the treated waste
did not consistently meet California state regulatory thresholds; (6) the
short-term physical stability of the treated waste was good, with
unconfined compressive strengths well above landfill solidification
recommendations; (7) due to the addition of reagents, treatment
resulted in a volume increase of 59 to 75 percent (68 percent average)
and a slight bulk density increase; (8) six-month monitoring showed
increased concentrations of the contaminants released from the treated
waste; (9) eighteen-month monitoring showed improved percent
reductions for arsenic and PCP relative to the 6-month cured sample
IV
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Abstract (Continued)
test results; chromium and copper showed slight to moderate increases
in leachate concentrations over time; and unconfined compressive
strengths increased an average of 71 percent relative to the 28-day
values; (10) the reagent cost to treat a cubic yard of contaminated
waste using STC's technology is estimated to range from $80 to $153
depending on the initial organic content of the waste; and (11)
treatment processing costs are expected to range from $40 to $175 per
cubic yard when used to treat 15,000 cubic yards of waste similar to
that found at the STC demonstration site.
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Table of Contents
Section Page
Notice ii
Foreword Hi
Abstract iv
Abbreviations xiv
Conversion of U.S. Customary Units to SI Units xvii
Acknowledgments xviii
1.0 Executive Summary 1
1.1 Introduction 1
.2 Overview of the SITE Demonstration 1
.3 Conclusions from the SITE Demonstration 2
.4 Results From the Case Studies 4
.5 Waste Applicability 4
.6 Economic Analysis 5
2.0 Introduction 7
2.1 Purpose, History, and Goals of the SITE Program 7
2.2 SITE Demonstration Documentation 8
2.3 Purpose of the Applications Analysis Report 8
2.4 Technology Description 9
2.4.1 Process Chemistry 9
2.4.2 Process Equipment 9
2.5 Key Contacts for the SITE Demonstration 11
3.0 Technology Applications Analysis 13
3.1 SITE Demonstration Results 13
3.2 Summary of Case Studies 19
3.3 Factors Influencing Performance and Cost Effectiveness 19
3.3.1 Waste Characteristics 19
3.3.2 Volume/Density Increase 20
3.3.3 Operating Conditions 20
3.3.4 Climate and Curing Conditions 21
VII
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Table of Contents (Continued)
Section Page
3.4 Site Characteristics and Logistics 21
3.4.1 Treatment Area 21
3.4.2 Site Access 21
3.4.3 Utilities 21
3.4.4 Equipment 22
3.4.5 Supplies and Services 22
3.4.6 Personal Protective Equipment 22
3.5 Materials Handling Requirements 22
3.5.1 Pretreatment Materials Handling 22
3.5.2 Residuals Handling 23
3.6 Personnel Requirements 23
3.7 Potential Community Exposures 23
3.8 Potential Regulatory Requirements 23
3.8.1 Resource Conservation and Recovery Act (RCRA) 24
3.8.2 Comprehensive Environmental Response, Compensation,
and Liability Act (CERCLA) 25
3.8.3 Toxic Substances Control Act (TSCA) 25
3.8.4 Clean Water Act (CWA) 25
3.8.5 Safe Drinking Water Act (SDWA) 26
3.8.6 Clean Air Act (CAA) 26
3.8.7 Atomic Energy Act (AEA) 26
3.8.8 Occupational Safety and Health Act 27
4.0 Economic Analysis 29
4.1 Assumptions 29
4.1.1 Waste Volume and Site Size 29
4.1.2 Major Technology Design and Performance Factors 29
4.1.3 Costs Sensitive to Specific Waste/Site Conditions 29
4.1.4 Financial Assumptions 30
4.2 Itemized Costs 30
4.2.1 Site Preparation Costs 30
4.2.2 Equipment Costs 30
4.2.2.1 Major Equipment Costs 30
4.2.2.2 Auxiliary Equipment Costs 31
Vlll
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Table of Contents (Continued)
Section Pace
4.2.3 Startup Costs 32
4.2.4 Supplies and Consumables 32
4.2.5 Labor 32
4.2.6 Utilities 32
4.2.7 Analytical Costs 33
4.2.8 Maintenance Costs 33
4.2.9 Site Demobilization 33
5.0 References 43
List of Tables
Table Page
3-1 Operating Parameters for the STC SITE Demonstration 14
3-2 Summary of TWA Data 14
3-3 Summary of TCLP Data 16
3-4 Summary of TCLP-Distilled Water Data 16
3-5 Summary of CALWET Data 16
3-6 Regulatory Thresholds for Critical Analytes of the SPT Waste 17
3-7 Summary of Permeability Data 18
3-8 Summary of Unconfined Compressive Strength Data 18
3-9 Summary of Volume Increase for STC-Treated Waste 18
4-1 STC Technology Design and Performance Factors 30
4-2 STC Technology Cost Comparison 31
4-3 Summary of Itemized Costs 34
List of Figures
Figure Pace
2-1 Schematic for STC Treatment Process 10
JX
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Appendix A
Vendor's Claims for the Technology
Table of Contents
Page
Introduction 47
STCs Immobilization Technology 47
Applications of the STC Technology 48
Summary 48
References 48
List of Figures
Figure Page
A-l Contaminated Soil Process Flow Diagram 49
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Appendix B
SITE Demonstration Results
Table of Contents
Section Pace
Introduction 53
Site Background 53
Site Description 54
Site Contamination Characteristics 54
SITE Demonstration Procedures 57
Review of Treatment Results 61
References 86
List of Tables
Table Page
B-l Analytical and Measurement Methods 62
B-2 Analytical Results for STC-Treated Wastes 64
B-3 Metal Analyses of Water and Sand Additives 69
B-4 Metal Analyses of Reagent Mixture (Sand Plus Reagents) 69
B-5 Analytical Results for CALWET 72
B-6 Results of TCLP, TCLP-Cage, and TCLP-Distilled Water for Treated Wastes 74
B-7 ANS 16.1 Leachate Analyses for STC-Treated Waste (Batch 3) 74
B-8 Oil and Grease Analysis 75
B-9 Analytical Results for pH, Eh, Loss on Ignition, and Neutralization Potential for
Raw and Treated Waste 76
B-10 Analytical Results for pH, Eh, Loss on Ignition and Neutralization Potential for
Sand, Water, and STC Reagent Mixture 76
B-l 1 Physical Characteristics of Raw Wastes and Sand 78
B-12 Physical Characteristics of STC-Treated Wastes and Reagent Mixture 78
B-13 Wet/Dry Weathering of STC-Treated Wastes 79
B-l4 Freeze/Thaw Weathering of STC-Treated Wastes 79
B-15 Petrographic Analysis of STC-Treated Wastes 81
B-l6 Abundance of Mineralogic Phases in X-ray Diffraction Analysis of Raw and
Treated Waste 82
B-17 Long-Term Test Results 83
B-l8 Long-Term (8-month) Chromium Analysis -- TCLP-Distilled Water (Batch 5) 86
B-19 Long-Term Physical Tests 86
XI
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List of Figures
Figure Page
B-l Regional Location Map - SPT Site, Selma, California 55
B-2 Areas of Contamination at the SPT Site 56
B-3 SPT SITE Demonstration Layout 58
Xll
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Appendix C
Case Studies
Table of Contents
Section
Introduction 89
Case Study C-l Tacoma Tar Pits, Tacoma, Washington 90
Case Study C-2 Purity Oil Sales Site, Fresno, California 109
Case Study C-3 Kaiser Steel Corporation, Fontana, California 115
Case Study C-4 Brown Battery Breaking Superfund Site, Reading, Pennsylvania .... 128
Case Study C-5 Lion Oil Company, El Dorado, Arkansas 129
References 136
List of Tables
Table Page
C-l-1 Treatability Test Results for Raw and Treated Wastes from the Tacoma
Tar Pits (Tar Pit) 92
C-l-2 Treatability Test Results for Raw and Treated Wastes from the Tacoma
Tar Pits (Tar Boils) 93
C-l-3 Treatability Test Results for Raw and Treated Wastes from the Tacoma
Tar Pits (North Pond) 95
C-1 -4 Treatability Test Results for Raw and Treated Wastes from the Tacoma
Tar Pits (South Pond) 97
C-l-5 Treatability Test Results for Raw and Treated Wastes from the Tacoma
Tar Pits (Auto Fluff) 99
C-l-6 STC-Treated Waste Composition 100
C-l-7 STC Raw Waste Analytical Results 103
C-l-8 TCLP Analytical Results for STC-Treated Wastes 105
C-l-9 Physical Test Results of STC-Treated Waste 107
C-2-1 Analytical Results for Purity Waste Ill
C-3-1 Analytical Results for KSC Waste 116
C-3-2 Summary of Physical Analysis of KSC Waste 127
C-4-1 Lead Analyses for Untreated Brown Battery Plant Soils 128
C-4-2 Lead Analyses for Treated Brown Battery Plant Soils 128
C-5-1 Analytical Results of Metal Concentrations from the Lion Oil Refinery
Treated Sludge 130
C-5-2 Analytical Results of Volatile and Semivolatile Organic Compounds from
the Lion Oil Refinery Treated Sludge 131
C-5-3 Solidification Results for the Lion Oil Refinery Sludge 132
Xlll
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Abbreviations
AAR
ACI
AEA
amp
ANS
ARAR
ASTM
CAA
CEPA
CALWET
CERCLA
CFR
cm
CRWQCB
CWA
°C
DL
DOE
DOT
EDX
Eh
EP
EPA
ESBL
FIT
FRTL
ft
FTIR
g
gal
HCP
HOPE
hp
hr
HRS
HSL
HSWA
kg
L
Ibs
LDR
LI
meq
mg
mo
mm
Applications Analysis Report
American Concrete Institute
Atomic Energy Act
ampere
American Nuclear Society
Applicable or Relevant and Appropriate Requirements
American Society for Testing and Materials
Clean Air Act
California Environmental Protection Agency
California Waste Extraction Test
Comprehensive Environmental Response, Compensation, and Liability Act
Code of Federal Regulations
centimeter
California Regional Water Quality Control Board
Clean Water Act
degree Celsius
Detection Limits
Department of Energy
Department of Transportation
Energy Dispersive X-ray
Oxidation/Reduction Potential
Extraction Procedure
Environmental Protection Agency
Engineering-Science, Inc. Berkeley Laboratory
Field Investigation Team
Federal Regulatory Threshold Limit
feet
Fourier Transform Infrared Spectroscopy
gram
gallon
Hazard Communication Program
High-Density Polyethylene
horsepower
hour
Hazard Ranking System
Hazardous Substance List
Hazardous and Solid Waste Amendments
kilogram
liter
pounds
Land Disposal Restrictions
Leachability Index
milliequivalents
milligram
month
millimeter
xiv
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Abbreviations (Continued)
MSDS
mV
NA
NAPL
NC
ND
NIOSH
NPDES
NPL
NRC
ORD
OSHA
OSWER
PAH
PCB
PCDD
PCDF
PCP
POTW
PPE
ppb
ppm
psi
QA/QC
QAPjP
RCRA
RFP
RI/FS
RM
ROD
SARA
SDWA
sec
SEM
SI
SITE
SPT
STC
STLC
TCLP
TCP
TER
TMSWC
TPH
TSCA
TSDF
TTLC
Material Safety Data Sheets
millivolts
Not Analyzed
Non-Aqueous Phase Liquid
Not Calculable
Not Detected
National Institute for Occupational Safety and Health
National Pollutant Discharge Elimination System
National Priority List
Nuclear Regulatory Commission
Office of Research and Development
Occupational Safety and Health Administration
Office of Solid Waste and Emergency Response
Polycyclic Aromatic Hydrocarbon
Polychlorinated Biphenyl
Polychlorinated Dibenzo-p-Dioxin
Polychlorinated Dibenzofuran
Pentachlorophenol
Publicly Owned Treatment Works
Personal Protective Equipment
parts per billion
parts per million
pounds per square inch
Quality Assurance/Quality Control
Quality Assurance Project Plan
Resource Conservation and Recovery Act
Request For Proposal
Remedial Investigation/Feasibility Study
Reagent Mixture
Record of Decision
Superfund Amendments and Reauthorization Act
Safe Drinking Water Act
second
Scanning Electron Microscopy
International System of Units
Superfund Innovative Technology Evaluation
Selma Pressure Treating
Silicate Technology Corporation
Solubility Threshold Limit Concentration
Toxicity Characteristic Leaching Procedure
Tetrachlorophenol
Technology Evaluation Report
Test Methods for Solidified Waste Characterization
Total Petroleum Hydrocarbons
Toxic Substances Control Act
Treatment, Storage, and Disposal Facility
Total Threshold Limit Concentration
xv
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Abbreviations (Continued)
TWA Total Waste Analysis
UCS Unconfined Compressive Strength
UIC Underground Injection Control
VOC Volatile Organic Compound
wk week
yd yard
yr year
XRD X-ray Diffraction
xvi
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Conversion of U.S. Customary Units to SI Units
Length
Volume
Mass
Temperature
Note:
inches x
inches x
inches x
feet x
gallons x
cubic yards x
pounds x
short tons x
5/9 x
1000 liters
1000 kilograms
25.4
2.54
0.0254
0.3048
3.785
0.7646
0.4536
0.9072
(° Fahrenheit - 32) =
= 1 cubic meter
= 1 metric ton
millimeters
centimeters
meters
meters
liters
cubic meters
kilograms
metric tons
0 Celsius
XVll
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Acknowledgments
This document was prepared under the direction of Mr.
Edward R. Bates, U.S. EPA SITE project manager, Risk Reduction
Engineering Laboratory, Cincinnati, OH. Contributors to and
reviewers of this report include Ed Bates and Patricia Erickson,
U.S. EPA, Cincinnati, OH; Greg Maupin, Silicate Technology
Corporation, Scottsdale, AZ; Amy Tarleton and Susan Fullerton,
Engineering- Science Inc., Fairfax, VA; Presbury West,
Construction Technology Laboratories, Inc., Skokie, IL; Jim Bob
Owens and Jean Youngerman, Radian Corporation, Austin, TX;
Paul Dean, David Liu, Robert Foster, Patricia Murphy, and Susan
Patterson of PRC Environmental Management, Inc.
This report was prepared for the EPA's Superfund
Innovative Technology Evaluation (SITE) program by Ingrid Klich
and Jim Styers, edited by Lori Brasche, and word processed by
Debra Johnston, Kamlah McKay, and Gay Phillips, all of PRC
Environmental Management, Inc., under Contract Nos. 68-03-3484
and 68-CO-0047. Paul Dean served as project manager for PRC
Environmental Management, Inc.
xvni
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Section 1.0
Executive Summary
1.1 Introduction
The Silicate Technology Corporation (STC)
immobilization technology is a solidification/
stabilization treatment process that was evaluated
under the Superfund Innovative Technology
Evaluation (SITE) program of the U.S.
Environmental Protection Agency (EPA). This
immobilization technology is designed to treat
organic and inorganic contaminants and thereby
reduce the mobility and leaching potential of
these constituents in contaminated soils and
sludges. For purposes of this report,
"solidification" refers to the physical
consolidation of contaminated soil into a hard,
rock-like material. "Stabilization" refers to the
chemical immobilization of hazardous
contaminants. STC's proprietary silicate-
mineral reagents bind the contaminants within a
layered alumino-silicate structure prior to
encapsulating the waste in a concrete-like
material, thus producing a high-strength, leach-
resistant monolith.
The STC technology demonstration was
performed at the Selma Pressure Treating (SPT)
site in Selma, California during November, 1990.
In general, the STC technology demonstration
had the following four objectives:
• Assess the technology's ability to
stabilize organic and inorganic con-
taminants.
• Assess the structural characteristics
of the solidified waste and the effec-
tiveness of stabilization over a 3-
year period.
• Determine volume and density
increases resulting from the
treatment process.
• Develop information required to
estimate the capital and operating
costs for the treatment system.
The purpose of this report is to present
information from the SITE demonstration and
additional case studies that is useful for assessing
the applicability of the STC immobilization
technology at Superfund, Resource Conservation
and Recovery Act (RCRA), and uncontrolled
hazardous waste sites. Section 2 presents an
overview of the SITE program, a description of
the STC technology, and a list of contacts for the
technology demonstration. Section 3 discusses
information relevant to the technology's applica-
tion, such as site characteristics, operating and
maintenance requirements, potential community
exposures, and potentially applicable environ-
mental regulations. Section 4 summarizes the
costs associated with implementing the technolo-
gy. Appendices A through C include the follow-
ing: the vendor's claims regarding the treatment
of organic and inorganic hazardous wastes,
sludges, and contaminated soil material; a sum-
mary of the results from the SITE demonstration;
and five summaries of case studies.
1.2 Overview of the SITE Demonstration
The SPT site was selected to evaluate the
effectiveness of STC's immobilization technology
for soils contaminated with both organic and
inorganic constituents. The waste material was
reported to contain pentachlorophenol (PCP;
1,900 to 8,400 parts per million (ppm)), arsenic
(375 to 1,900 ppm), chromium (1,900 ppm), and
copper (1,500 ppm). In addition, oil and grease
levels ranged from 10,000 to 20,000 ppm. Prior
to treatment, soil pH was slightly acidic to
neutral and moisture content ranged from 4 to 6
percent (COM, 1989 and U.S. EPA, 1990a).
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During the SITE demonstration, approxi-
mately 16 tons of contaminated soil material
were treated. STC's proprietary alumino-silicate
compounds were added to the waste to chemical-
ly fix, and thereby stabilize heavy metals and
semivolatile organic constituents. Addition of a
silicate solidifying agent microencapsulates the
adsorbed contaminants, thereby producing an
additional physical barrier to leaching.
The STC technology demonstration required
6 days to complete once all of the treatment
equipment was set up. Initial processing consist-
ed of treating a clean sand with a mixture of
STC's proprietary SOILSORB reagents (P-4 and
P-27). On each of the following 5 days, one
2.5-cubic-yard batch of contaminated soil was
treated. Surface "hardpan" and sand from an
unlined, dry waste disposal pond was collected to
a depth of 2 to 3 feet and thoroughly mixed
prior to the addition of the STC reagents and
water. The surface "hardpan" consisted of PCP-
soaked and encrusted sand resulting from 40
years of wood treating operations. Significant
inhomogeneity in the treated waste from Batch
2 resulted in pretreatment screening of the
remaining batches (3 through 5) and led to the
exclusion of Batch 2 from further analysis.
Samples of raw and treated waste were
submitted for chemical and physical character-
ization. Analytical testing was targeted towards
selected inorganic constituents (arsenic, chromi-
um, and copper) and organic contaminants
(primarily PCP), using various leach tests plus
total waste analysis (TWA) extraction proce-
dures. EPA SW-846 Methods 8240 and 8270
were used for TWA of volatile and semivolatile
organic compounds, respectively. TWA for
metals was performed on acid extracts using
EPA SW-846 Methods 3010, 3020, 3050, 6010,
7060, 7421, 7740, 7841, 7471, and 7470 (U.S.
EPA, 1986b). Leach tests included the EPA SW-
846 Method 1311 Toxicity Characteristic Leach-
ing Procedure (TCLP), modified
TCLP-Distilled Water and TCLP-Cage tests, the
California Waste Extraction Test (CALWET) as
described in the California Health and Safety
Code, Section 66700, and a modified version of
the American Nuclear Society (ANS) 16.1 (ANS,
1986). Additional chemical and physical charac-
terization of the raw and/or treated waste in-
cluded pH, Eh, loss on ignition, neutralization
potential, particle size analysis, bulk density,
permeability, unconfined compressive strength,
wet/dry and freeze/thaw analyses, petrographic
examination, X-ray diffraction, scanning elec-
tron microscopy, and Fourier transform infrared
spectroscopy (U.S. EPA, 1990b).
1.3 Conclusions from the SITE Demonstra-
tion
To constitute treatment under Superfund,
immobilization (i.e., solidification/stabilization)
technologies must chemically limit the mobility
of the contaminants. Specifically, before a
technology can be selected as a treatment alter-
native, EPA guidance suggests that an immobili-
zation technology demonstrates a significant
reduction (i.e., a 90 to 99 percent reduction) in
the mobility of chemical constituents of concern
(OSWER Directive No. 9200.5-220). The reduc-
tion in mobility is evaluated using the TCLP for
inorganics and TWA for semivolatile organics.
In addition, federal and state regulatory thresh-
olds must be met to allow for legal disposal as
nonhazardous wastes either on site or in landfills.
The following conclusions about the
effectiveness and cost of STC's solidifica-
tion/stabilization treatment process are based on
results of analytical data and general
observations from this SITE demonstration as
discussed in Section 4 and Appendix B of this
report.
PCP (Targeted for treatment):
• TWA extract concentrations of PCP
were reduced 91 to 97 percent.
• TWA extract concentrations of PCP
were well above the California state
regulatory threshold level of 17 ppm
for total waste prior to and after
treatment.
• TCLP leachate concentrations of PCP
varied from negative percent reduc-
tions to greater than 81 percent re-
duction.
• TCLP-Distilled Water leachate con-
centrations of PCP were reduced 80
to 97 percent.
• PCP concentrations were well below
the federal regulatory threshold
TCLP level of 100 ppm prior to and
after treatment.
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• CALWET leachate concentrations of
PCP were above California's solubil-
ity threshold level of 1.7 ppm prior
to and after treatment.
• Stabilization of semivolatile organic
compounds (exclusive of PCP) and
volatile organic compounds could not
be evaluated due to the low concen-
trations of these analytes in the raw
waste.
Arsenic (Targeted for treatment):
• TCLP leachate concentrations of
arsenic were reduced 35 to 92 per-
cent.
• TCLP-Distilled Water leachate con-
centrations of arsenic were reduced
98 percent or more.
• Arsenic concentrations were below
the federal regulatory threshold
TCLP level of 5.0 ppm prior to and
after treatment.
• CALWET leachate concentrations of
arsenic were both above and below
California's solubility threshold level
of 5.0 ppm after treatment.
• TWA extract concentrations of
arsenic were both above and below
the California state regulatory
threshold level of 500 ppm for total
waste prior to and after treatment.
Chromium (Not targeted for treatment):
• TCLP leachate concentrations of
chromium were increased as a result
of treatment.
• TCLP-Distilled Water leachate con-
centrations of chromium varied from
-42 to 54 percent reduction.
• Chromium concentrations were
below the federal regulatory
threshold TCLP level of 5.0 ppm
prior to and after treatment.
• CALWET leachate concentrations of
chromium were well below
California's solubility threshold
level of 560 ppm prior to and
after treatment.
• TWA extract concentrations of chro-
mium were below the California
state regulatory threshold level of
2,500 ppm for total waste prior to
and after treatment.
Copper (Not targeted for treatment):
• TCLP leachate concentrations of
copper were reduced 90 to 99 per-
cent.
• TCLP-Distilled Water leachate con-
centrations of copper were reduced
86 to 90 percent.
• CALWET leachate concentrations of
copper were both above and below
California's solubility threshold level
of 25 ppm prior to and after treat-
ment.
• TWA extract concentrations of
copper were below the California
state regulatory threshold level of
2,500 ppm for total waste prior to
and after treatment.
Long-Term Results:
• TCLP-extracts for metals and TWA
for PCP of the 6-month cured sam-
ples showed increased concentrations
of contaminants released from the
treated waste.
• Analyses for the 18-month cured
samples showed improved percent
reductions relative to the 6-month
cured sample test results for arsenic,
averaging 88 percent reduction, and
PCP averaging 96 percent reduction.
Chromium and copper concentrations
showed slight to moderate increases
in the TCLP-extracts over time.
Physical Properties:
• Unconfined compressive strength
(UCS) of the treated wastes was
moderately high, averaging 260 to
-------
350 pounds per square inch (psi).
Eighteen-month UCS tests show
an average 71 percent increase in
physical strength with time,
averaging 760 to 1,400 psi.
• The relative cumulative weight loss
after 12 wet/dry and 12 freeze/thaw
cycles was negligible (less than
1 percent).
• Permeability of the treated waste was
low (less than 1.7 x 10"7 cm/sec).
• Due to the addition of reagents,
treatment of the wastes resulted in
volume increases ranging from 59 to
75 percent (68 percent average), with
slight increases in bulk density.
• Petrographic and scanning electron
microscopy examinations indicate
good binder-to-aggregate bonding.
Constituents comprising the reagent
mix binder included calcium hydro-
xide, glass, portland cement, and
black pigment. Soil constituents
were predominantly quartz and feld-
spar with minor hornblende and
trace mica.
Treatment Technology:
• No equipment-related problems
occurred during the 6-day techno-
logy demonstration.
• The process equipment used during
the demonstration was capable of
mixing all components, including the
waste material, into a homogeneous,
solidified product, provided that
pretreatment screening or size re-
duction of surface hardpan material
down to 0.04 - 0.08 inch (1-2 mm)
was conducted.
Unit Costs:
• The STC treatment process is
expected to cost approximately $190
to $330 per cubic yard when used to
treat large amounts (15,000 cubic
yards) of waste similar to that found
at the STC demonstration site.
• Reagent costs are estimated to range
from $80 to $153 per cubic yard
depending on initial total organic
content of the waste.
• Processing costs are estimated to
range from approximately $40 to
$175 per cubic yard of waste.
1.4 Results From the Case Studies
Information on the STC immobilization
technology's performance at the following five
facilities was evaluated to provide additional
performance data:
1. Tacoma Tar Pits, Tacoma, Washington
2. Purity Oil Sales Site, Fresno, California
3. Kaiser Steel Corporation, Fontana, Cali-
fornia
4. Brown Battery Breaking Superfund Site,
Reading, Pennsylvania
5. Lion Oil Refinery, El Dorado, Arkansas
Results from the five case studies, summa-
rized in Appendix C, suggest that the STC
solidification/stabilization treatment process is
capable of chemically stabilizing selected inor-
ganic and organic contaminants from waste
material ranging in consistency from soils to
sludges. Limited solidification test data also
suggest that the technology is able to produce a
solidified monolith from contaminated sludges as
well as soils. Much of the information obtained
from these case studies pertains to chemical
analyses from preliminary treatability studies
performed at the above sites. The first three
case studies were conducted under the SITE
program as preliminary investigations to the STC
SITE demonstration. The various chemical and
leach tests used to evaluate STC's technology
performance at the individual sites include
TCLP, TWA, EP Toxicity, ANS 16.1, and
CALWET.
1.5 Waste Applicability
The STC solidification/stabilization
treatment process can be applied to contaminated
soils containing both inorganic and semivolatile
organic constituents as shown by this SITE
demonstration and several case studies.
Treatability testing is necessary to determine the
amount of reagents necessary for adequate
solidification/stabilization according to
-------
variations in organic and inorganic contaminant
concentrations. In addition, STC reports that its
technology can also remove organics from
ground water and chemically stabilize both
organics and inorganics in hazardous waste
sludges. Potential sites for applying this
technology to contaminated soils and sludges
include Superfund and RCRA corrective action
sites where semi- or nonvolatile organics or
inorganics, or a combination of the contaminants
exists. STC indicates that this treatment process
is not recommended for wastewater
contaminated with low-molecular-weight
organic contaminants such as alcohols, ketones,
and glycols.
1.6 Economic Analysis
Major factors and assumptions in evaluating
the cost of the STC technology include: (1) waste
volume and site size; (2) technology design and
performance factors; (3) technology operating
requirements; (4) utilization rates and
maintenance schedules; (5) variability in waste
type and site conditions; and (6) financial
factors, such as depreciation, interest rates, and
utility costs.
Itemized treatment costs for the STC tech-
nology include: (1) site preparation costs;
(2) equipment costs, including both major
equipment costs and auxiliary equipment costs;
(3) startup costs; (4) supplies and consumables;
(5) labor; (6) utilities; (7) analytical costs;
(8) maintenance costs; and (9) site demobilization
costs. The total treatment cost for the STC
technology for remediating 15,000 cubic yards of
waste contaminated with similar constituents as
those found at the SPT site was estimated to
range from $2,843,534 to $4,913,308 depending
on mixer size and duration of mixing. This cost
equates to approximately $190 to $330 per cubic
yard of raw waste; supplies, labor, and analytical
expenses account for the largest portions of the
total treatment cost. Contaminated soil at sites
containing negligible concentrations of organics
could be treated at an estimated cost as low as
$120 to $255 per cubic yard of raw waste. The
reagent cost to treat a cubic yard of waste ranged
from $80 to $153 depending on the initial total
organic content of the soil. Processing costs
ranged from approximately $40 to $175 per
cubic yard of waste. Off-site transport and
disposal could significantly increase this esti-
mate. Section 4 describes the assumptions and
procedures used in determining the technology
costs.
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Section 2.0
Introduction
This section of the Applications Analysis
Report includes a description of the Superfund
Innovative Technology Evaluation Program, a
discussion of the specific purpose of this report,
and a general description of the hazardous waste
remediation technology developed by Silicate
Technology Corporation (STC).
2.1 Purpose, History, and Goals of the SITE
Program
The Superfund Amendments and Reauthori-
zation Act of 1986 (SARA) prompted two offic-
es of the U.S. Environmental Protection Agency
(EPA), the Office of Solid Waste and Emergency
Response (OSWER) and the Office of Research
and Development (ORD), to establish a formal
program called the Superfund Innovative Tech-
nology Evaluation (SITE) Program. This pro-
gram promotes the development and use of
innovative technologies to clean up hazardous
waste sites across the country. The primary
purpose of the SITE Program is to enhance the
development and demonstration, and thereby
promote the commercial availability, of innova-
tive technologies applicable to Superfund sites.
The major goals of the SITE Program are:
• Identify and remove impediments to
the development and commercial use
of alternative technologies.
• Demonstrate the more promising
innovative technologies in order to
establish reliable performance and
cost information for site cleanup
decision making.
• Develop procedures and policies that
encourage selection of available al-
ternative treatment remedies at
Superfund sites.
• Structure a development program
that nurtures emerging technologies.
EPA recognizes that a number of factors
inhibit the expanded use of alternative technolo-
gies at Superfund sites. One of the objectives of
the program is to identify these impediments and
remove them or develop methods to promote the
expanded use of alternative technologies. An-
other objective of the SITE Program is to dem-
onstrate and evaluate selected technologies. This
is a significant ongoing effort that involves
ORD, OSWER, EPA regional offices, and the
private sector.
The SITE program is comprised of four
component programs including:
• Demonstration Program
• Emerging Technologies Program
• Measurement and Monitoring Tech-
nologies Program
• Technology Transfer Program
This report is a product of the SITE Demon-
stration Program, which is designed to test field-
ready technologies and provide reliable engi-
neering performance and cost data on selected
alternative hazardous waste remediation technol-
ogies. Developers of innovative waste cleanup
technologies apply to the demonstration program
by responding to EPA's annual request for
proposals (RFP). Each annual round of demon-
strations includes approximately 10 new technol-
ogies. To qualify for the program, a new tech-
nology must be at the pilot- or full-scale stage of
development and offer some advantage over
existing cleanup technologies. Mobile technolo-
gies are of particular interest to EPA. Proposals
are evaluated by OSWER and ORD staff to select
-------
or determine those technologies with the most
promise for use at hazardous waste sites. Once
a proposal has been accepted, a cooperative
agreement between EPA and the developer is
established to set forth responsibilities for con-
ducting the demonstration and evaluating the
technology. The developer is responsible for
demonstrating the technology at the selected site,
and assuming all costs to transport, operate and
remove the equipment. EPA is responsible for
project planning, sampling and analysis, quality
assurance and quality control, preparing reports,
and disseminating information.
Demonstrations are conducted at hazardous
waste sites (usually Superfund sites) or under
conditions that closely simulate actual wastes and
conditions, to ensure accuracy and reliability of
information collected. Data obtained during a
demonstration are used to evaluate the perfor-
mance of the technology and potential operating
problems, in addition to assessing estimated
capital and operating costs. Demonstration data
also provide useful information for estimating
long-term operating and maintenance costs and
evaluating long-term risks in using the technolo-
gy.
The other three component SITE Programs
listed above focus primarily on fostering further
investigations and development of treatment
technologies that are still at the laboratory scale
through the Emerging Technologies Program,
and providing assistance in the development and
demonstration of innovative monitoring and site
characterization technologies through the Mea-
surement and Monitoring Technologies Program.
Finally, the Technology Transfer Program
prepares a variety of publications including
reports, videos, bulletins, and project summaries.
This information is distributed to the user com-
munity to provide reliable technical data for use
by decisionmakers, such as remedial project
managers and facility managers in selecting
remedial technologies, and to promote the tech-
nology's commercial use.
2.2 SITE Demonstration Documentation
Results of the STC SITE demonstration
project are contained in two documents, the
Technology Evaluation Report (TER) and the
Applications Analysis Report (AAR). The TER
presents demonstration testing procedures, data,
and quality assurance/quality control standards,
and it also provides a comprehensive description
of the demonstration and its results. The TER
parallels the AAR and is intended for technical
professionals making detailed evaluations of the
technology for a specific site and waste situation.
The AAR evaluates available information on
the specific technology and analyzes its overall
applicability to other situations with different
site characteristics, waste types, and waste matri-
ces. This report summarizes the results of the
SITE demonstration, the vendor's design and test
data, and other laboratory and field applications
of the technology. It discusses the advantages,
disadvantages, and limitations of the technology.
Costs of the technology for different applications
are estimated based on available data from this
and other similar SITE demonstrations. The
report also discusses the factors, such as site and
waste characteristics, that have a major effect on
costs and performance.
2.3 Purpose of the Applications Analysis
Report
The purpose of the AAR is to estimate,
based on available data, the applicability and
costs of a technology for Superfund and RCRA
hazardous waste site remediations. This report is
intended for the decisionmakers responsible for
implementing specific remedial actions and helps
them determine whether a technology has merit
as an option for a particular cleanup situation.
There are, however, limits to conclusions
regarding Superfund applications that can be
drawn from a single field demonstration. The
successful demonstration of a technology at one
site does not assure that a technology will be
widely applicable or fully developed for com-
mercial use. Data obtained from this demonstra-
tion may have to be extrapolated to estimate the
total operating range of the technology. The
extrapolation can be based on both demonstra-
tion data and other information available on the
technology, including case studies of varying
waste contamination.
The Applications Analysis Report attempts to
synthesize existing information and draw reason-
able conclusions. This document will be useful
to those considering the technology for Super-
fund cleanup and represents a critical step in the
development and commercialization of the
treatment technology. If a candidate technology
-------
appears to be suitable for a specific site, a more
thorough analysis would be made based on the
TER and on available information from remedial
investigations for the specific site.
2.4 Technology Description
STC's contaminated soil process utilizes
silicate compounds to chemically stabilize organ-
ic and inorganic constituents in contaminated
soils and sludges. The vendor claims that pro-
prietary silicate reagents adsorb and chemically
fix organic and inorganic contaminants prior to
solidifying the waste with a cementitious materi-
al resulting in a high-strength, leach-resistant
monolith. Treatability studies and site investiga-
tions are conducted to determine the necessary
type and amounts of reagents according to the
waste characteristics. The following sections
discuss information provided by STC and in-
clude the general treatment process chemistry
and major process equipment needed for the
STC technology. Specific procedures used in the
SITE demonstration are detailed in Appendix B.
2.4.1 Process Chemistry
STC has developed two groups of reagents:
SOILSORB HM for treating wastes with inor-
ganic constituents and SOILSORB HC for treat-
ing wastes with organic constituents. These two
groups of reagents can be combined to treat
wastes containing both organic and inorganic
contaminants.
Stabilization of wastes with inorganic con-
stituents involves silicate-forming reactions
resulting in the incorporation of heavy-metal
ions into the crystal lattice structure of a highly
insoluble calcium-alumino-silicate compound.
The reactions effectively immobilize the con-
taminants, thereby reducing the potential for
leaching. A silicate solidifying agent micro-
encapsulates the alumino-silicate compound to
form another physical barrier to leaching. The
result is a very stable compound analogous to
common rock-forming silicate minerals.
STC's technology for treating organic wastes
utilizes a three-step process in which organic
compounds in the waste are sequestered by a
modified alumino-silicate mineral. The silicate
is surface-modified with organic compounds,
creating a layered structure that consists of
organic layers sandwiched between the alumino-
silicate layers. Upon mixing with the organic
wastes, this modified silicate bonds organic
contaminants into the layers of the organically
surface-modified alumino-silicate compound
through a partitioning reaction. STC claims that
the organic layers of the modified silicate can
adsorb as much as 20 times their own weight of
organic constituents.
The first step of the contaminant stabiliza-
tion process involves partitioning similar to a
liquid/liquid extraction. If a water-immiscible
oil and water that contains a polynuclear aromat-
ic compound such as anthracene are combined,
the anthracene will migrate into the oil phase
and remain there. STC's immobilization tech-
nology is based on this concept except that it
utilizes a solid organic phase instead of oil. This
partitioning follows basic laws of physical chem-
istry and can in general terms be predicted for
any organic compound based on its water solu-
bility.
The second step of stabilization involves the
morphology of the alumino-silicate structure.
As the organic constituents partition to the
organic layers of the surface-modified silicate,
the layered alumino-silicate plates tend to bond
with the surface of the waste, thereby creating a
physical barrier and thus reducing leachability.
Finally, the third step is the addition of
STC's proprietary silicate solidifying agent,
which microencapsulates the layered alumino-
silicate structure and bonds the solidifying agent
to the exposed layered-silicate surfaces. This
microencapsulation of the adsorbed organics
further reduces leachability by forming another
physical barrier to leaching. The alumino-
silicates used for the organic partitioning reac-
tion and the silicates used for the microencapsu-
lation reaction can be shown to be thermody-
namically stable compounds, analogous to com-
mon, rock-forming silicate minerals. The ven-
dor-claimed durability will be tested in the long-
term storage phase of this demonstration.
2.4.2 Process Equipment
Treatment of contaminated soil (Figure 2-1)
typically begins with the separation of coarse
material from fine material in a mechanical
separator. This is accomplished using a shaker
screen to separate the coarse material greater
than 3/8 inch in diameter. This coarse material
-------
01
o
c
C/3
•O
a
I
10
-------
is sent through a shredder or crusher, which
reduces the waste material to less than 3/8 inch.
The screened waste is loaded into a batch plant
where it is weighed and the appropriate amount
of silicate reagents determined during treatabil-
ity testing are added. This mixture is conveyed
to a pug mill mixer (or equivalent, such as a
ready-mix cement truck) where water is added
and the mixture is thoroughly blended. Sludges
are placed directly into the pug mill for addition
of reagents and mixing. The amount of reagents
required for stabilization can be adjusted ac-
cording to variations in organic and inorganic
contaminant concentrations determined during
treatability testing. The mixing process contin-
ues until the operator determines that the waste
and the added reagents are thoroughly homoge-
nized, up to approximately 60 minutes per batch.
The treated material is then placed in confining
pits for on-site curing, or cast into molds for
transport and disposal off site.
Hardware for the treatment process includes
processing and materials-handling equipment.
With the exception of STCs liquid reagent
metering equipment, conventional construction
equipment readily available for purchase or
rental in most areas can be used. Such equip-
ment typically would have the capacity to treat
up to 40 cubic yards of contaminated soil per
day; however, only 2.5 cubic yards per day were
processed during this demonstration.
Process equipment for soil treatment using
STC's technology includes the following:
• Pretreatment screen -- Pretreatment
screening is normally accomplished
with a shaker screen to separate fine
(<3/8 inch in diameter) from coarse
material (>3/8 inch in diameter).
Pretreatment screening down to 0.04
- 0.08 inch (1-2 mm) diameter was
required for the STC demonstration
since a crusher was not used, and it
was necessary to ensure that individ-
ual aggregates of untreated waste did
not bias the chemical analyses.
• Crusher or shredder — A crusher or
shredder is used to further reduce
waste aggregate size prior to mixing,
if necessary.
• Weight conveyor — The weight con-
veyor is used to weigh and transfer
screened material to the pug mill.
• Pug mill — A pug mill, cement-mixer,
or other conventional construction
equipment can be used as a mixing ves-
sel.
• Liquid reagent metering equipment —
Liquid reagent metering is accomplished
with STCs mobile liquid meter, which is
mounted on a 20-foot bed trailer. This
equipment includes two 500-gallon tanks.
Materials-handling equipment for soil treat-
ment includes the following:
• Front-end loader/backhoe for exca-
vation and transport of waste materi-
al on site.
• All-terrain forklift for moving 1.5-
to 2-ton forms filled with treated
waste, if needed.
2.5 Key Contacts for the SITE Demonstra-
tion
Additional information concerning the STC
solidification/stabilization treatment process or
the SITE Program can be obtained from the
following sources:
The STC Technology:
Mr. Steve Pegler or Mr. Greg Maupin
Silicate Technology Corporation
7655 E. Gelding Rd.
Scottsdale, Arizona 85260
(602) 948-7100
The SITE Program:
Mr. Edward R. Bates
Superfund Technology Demonstration
Division
U.S. EPA Risk Reduction Engineering
Laboratory
26 West Martin Luther King Drive
Cincinnati, Ohio 45268
(513) 569-7774
11
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Section 3.0
Technology Applications Analysis
This section addresses the applicability of the
STC immobilization (i.e., solidification/stabili-
zation) technology for the treatment of contami-
nated soil containing heavy metals and penta-
chlorophenol (PCP). For purposes of this report,
"solidification" is defined as the physical consoli-
dation of contaminated soil into a hard, rock-
like material. "Stabilization" is defined as the
chemical containment of hazardous contami-
nants. This discussion is based upon the results
of the SITE demonstration performed at the
Selma Pressure Treating (SPT) wood preserving
site in Selma, California, and a series of other
applications of the technology. The vendor's
claims concerning the capabilities of the STC
solidification/stabilization treatment process are
presented in Appendix A. A complete discus-
sion of the results of the SITE demonstration is
included in Appendix B. The results from five
case studies documenting the use of the STC
technology are presented in Appendix C.
Included in this section is a summary of the
effectiveness of the STC solidification/stabili-
zation treatment process followed by discussions
of the characteristics of the SPT site, the materi-
als-handling requirements for the STC technolo-
gy, personnel requirements, potential community
exposures resulting from application of the STC
technology, and potential regulatory require-
ments that may pertain to use of the technology.
3.1
SITE Demonstration Results
The STC solidification/stabilization treat-
ment process was used to treat contaminated
soils reported to contain elevated concentrations
of PCP (1,900 to 8,400 ppm), arsenic (375 to
1,900 ppm), chromium (1,900 ppm), and copper
(1,500 ppm) (CDM, 1989 and U.S. EPA, 1990a).
A summary of the results for other parameters is
found in Appendix B.
In general, the objectives of the STC SITE
demonstration were as follows:
• Assess the technology's ability to
stabilize organic and inorganic con-
taminants.
• Assess the structural characteristics
of the solidified waste and effective-
ness of stabilization over a 3-year
period.
• Determine volume and density in-
creases resulting from the treatment
process.
• Develop information required to
estimate the capital and operating
costs for the treatment system.
The field demonstration of the STC technol-
ogy was conducted over a period of 6 days. The
first day consisted of processing a reagent-blank
mixture batch that included clean sand, water,
and STC's proprietary SOILSORB reagents (P-4
and P-27). On days 2 through 6, STC treated
f ive 2.5-cubic-yard batches of contaminated soil.
Table 3-1 lists the operating parameters for the
STC SITE demonstration. Batch 2 was not
further analyzed due to mixing problems result-
ing in significant inhomogeneity of the treated
waste.
The key findings of the demonstration are
given below; a more detailed discussion is pro-
vided in Appendix B. All percent reductions
cited take into account the effects of dilution
due to the addition of treatment reagents.
A summary of the total waste analyses
(TWA) for the inorganic contaminants of regula-
tory concern at the SPT site, as well as PCP is
shown in Table 3-2. Raw waste concentrations
13
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Table 3-1. Operating Parameters for the STC SITE Demonstration
Parameters
Waste soil weight (Ibs)
Silica sand weight (Ibs)
Dry reagent weight (Ibs)
Water added (Ibs)
Water lost during curing (Ibs)
Mixer power (hp)
Current to mixer (amp-hr)
Pretreatment mixing time (min)
Treatment mixing time (min)
Additives ratio8
Batch
RM
0
1,972
695
422
NA
29
17
0
22
NC
1
5,000
0
1,732
2,172
97
29
83
50
60
0.761
2
5,000
0
1,723
3,850
NA
29
77
60
40
NC
3
4,000
0
1,382
1,713
41
29
77
60
40
0.764
4
4,000
0
1,413
1,760
71
29
248
270
60
0.776
5
4,464
0
1,638
1,759
67
29
79
60
45
0.746
RM = Reagent mixture
NA = Not analyzed
NC = Not calculated
a = The additives ratio is the mass of additives including water of hydration, divided by the mass
of wastes.
Table 3-2. Summary of TWA Data
Constituent
Arsenic
Chromium
Copper
PCP
Ranges of Concentrations (ppm)
(Batches 1, 3, 4, and 5)
Raw Waste
270 - 2,200
340 - 2,100
330 - 1,300
2,000 - 8,300
Treated Waste
200 - 1,600
270 - 1,300
210 - 780
80 - 170
Ranges of Percent
Reduction
-29 - (-4)
-48 - 4
-32 - 4
91 - 97
14
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ranged from 270 to 2,200 ppm for arsenic; 340 to
2,100 ppm for chromium; and 330 to 1,300 ppm
for copper. Treated waste TWA results show
slightly decreased concentrations for each of
these analytes. Taking into account the dilution
factor due to the added reagents, TWA results
indicate mostly negative percent reductions. As
discussed in more detail in the TER, increased
total metal concentrations following treatment is
presumed to be a result of differences in extrac-
tion efficiencies relative to the specific raw or
treated waste matrix. However, the STC treat-
ment process was not expected to destroy inor-
ganic contaminants, but rather immobilize them
from leaching. Therefore, although TWA for
selected inorganics were evaluated to compare
total contaminant concentrations with leachate
concentrations, the TWA is not considered a
useful criteria for the inorganic analytes. PCP
concentrations in the raw waste ranged from
2,000 to 8,300 ppm, with the treated waste
concentrations ranging from 80 to 170 ppm.
Percent reductions for PCP ranged from 91 to 97
percent, indicating that the STC treatment
process was effective in treating the organic
component of the SPT waste.
Tables 3-3 and 3-4 summarize TCLP and
TCLP-Distilled Water results, respectively.
Leach tests conducted on the SPT waste show
significant percent reductions in the leachate
from the raw waste to the leachate in the treated
waste for several of the critical analytes. Percent
reductions for arsenic ranged from 35 to 92
percent as measured by the TCLP, and 98 per-
cent based on the TCLP-Distilled Water test.
Percent reductions of copper concentrations in
the leachate, although not a target analyte for
treatment, ranged from 90 to 99 percent when
evaluated using the TCLP, and from 86 to 90
percent based on the TCLP-Distilled Water test.
Chromium was also not a target analyte for
treatment because of very low leachable concen-
trations. Nevertheless, chromium concentrations
in the raw waste leachates were reduced by up to
54 percent based on the TCLP-Distilled Water
test results; however, due to the very low con-
centrations of chromium in the raw and treated
waste TCLP leachates, no significant conclusions
could be drawn concerning the teachability of
chromium upon treatment as measured by the
TCLP test. Concentrations of PCP in the leach-
ate from the TCLP test showed increases upon
treatment for two batches resulting in percent
reductions ranging from -460 to greater than 81
percent, whereas the TCLP-Distilled Water test
showed percent reductions of 80 to 97 percent
from the raw waste to the treated waste.
Table 3-5 summarizes CALWET results for
both the raw and treated wastes. In general, the
CALWET consists of an extraction similar to that
of the TCLP extraction, except that the
CALWET uses a citric acid leaching solution for
a period of 48 hours at a liquid-to-solid ratio of
10 to 1. This procedure is a more aggressive
leaching procedure since it uses a stronger
leaching solution for a longer period of time.
The results from the CALWET method showed
very large negative percent reductions and in
several cases showed increased leachability of the
analytes from the raw to the treated wastes.
Specifically, chromium and PCP showed greater
leachate concentrations in the treated wastes than
in the raw wastes. Arsenic and copper showed
decreased leachate concentrations, but percent
reductions were low when accounting for dilu-
tion. Overall, due to the inconsistent and erratic
trends in the results of the CALWET procedure,
conclusions that can be drawn regarding the
effectiveness of the STC stabilization process are
based on achieving California thresholds as
described below.
Federal and state of California regulatory
thresholds for the TCLP and CALWET methods
are shown in Table 3-6. The concentrations of
arsenic, total chromium, and PCP were all below
federal regulatory threshold levels for the TCLP
in both the raw and treated wastes. Federal
threshold values for copper and hexavalent
chromium have not been established. California
regulatory thresholds are presented for total
threshold limit concentrations (TTLC) utilizing
TWA concentrations, and for solubility threshold
limit concentrations (STLC) for the CALWET
leach method. In general, arsenic and PCP
exceeded the TTLC for both the raw and treated
wastes. Total chromium and copper were below
TTLC levels for both raw and treated wastes.
CALWET leach data reveal more variable trends
with arsenic and copper ranging from below to
above threshold levels, PCP well above STLC
levels, and total chromium well below the regu-
latory levels for both raw and treated wastes. In
the state of California, regulatory levels are
specified both as total chromium (including
trivalent and hexavalent species) and as hexa-
valent chromium; however, data for hexavalent
chromium was not available. Thus, the STC
15
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Table 3-3. Summary of TCLP Data
Constituent
Arsenic
Chromium"
Copper*
PCP
Ranges of Concentrations (ppm)
(Batches 1,3,4, and 5)
Raw Waste
1.1 - 3.3
<0.05 - 0.27
1.4 - 9.4
1.5 - 2.3
Treated Waste
0.09 - 0.88
0.19 - 0.32
0.06 - 0.10
< 0.25 - 5.5
Ranges of Percent
Reduction
35 - 92
-390 - (-110)
90 - 99
-460 - >81
a Anafyte not a target for treatment.
Table 3-4. Summary of TCLP-Distilled Water Data
Constituent
Arsenic
Chromium"
Copper"
PCP
Ranges of Concentrations (ppm)
(Batches 1,3, 4, and 5)
Raw Waste
0.73 - 1.3
0.07 - 0.19
0.37 - 0.99
35 - 80
Treated Waste
< 0.010 - 0.012
< 0.050 - 0.079
0.030 - 0.054
0.58 - 4.0
Ranges of Percent
Reduction
>98
-42 - 54
86 - 90
80 - 97
* Anafyte not a target for treatment.
Table 3-5. Summary of CALWET Data
Constituent
Arsenic
Chromium"
Copper"
PCP
Ranges of Concentrations (ppm)
(Batches 1, 3, 4, and 5)
Raw Waste
8.8 - 29
2.1 - 7.1
18 - 61
2.3 - 3.2
Treated Waste
4.6 - 23
3.8 - 19
8.8 - 33
3.5 - 32
Ranges of Percent
Reduction
-44 - 37
-380 - (-210)
2 - 22
-1,800 - (-140)
Anafyte not a target for treatment.
16
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Table 3-6. Regulatory Thresholds for Critical Analytes of the SPT Waste
Constituents
Arsenic
Chromium (hexavalent)
Chromium (total)
Copper
PCP
Federal
FRTL (mg/L)"
5.0
—
5.0
—
100
State of California
TTLC (mg/kg)*
500
500
2,500
2,500
17
STLC (mg/L)e
5.0
5.0
560
25
1.7
a = Federal Regulatory Threshold Limit, based on TCLP.
b = Total Threshold Limit Concentration, based on TWA.
c = Solubility Threshold Limit Concentration, based on CALWET.
solidification/stabilization treatment process did
not consistently achieve California leaching
(CALWET) requirements for the treated wastes.
In addition, the treatment process also did not
lower total concentrations for contaminants that
exceeded California's TTLC in the raw waste
(i.e., arsenic and PCP); however, immobilization
processes are not intended to reduce total con-
taminant concentrations, but to reduce leachable
concentrations. Finally, TCLP leachate concen-
trations were already below federal threshold
TCLP levels prior to treatment.
The short-term structural characteristics of
the treated waste appeared to be suitable for the
waste to be placed in a hazardous waste landfill,
assuming appropriate environmental regula-
tions are met (e.g., land disposal restrictions
under RCRA). The permeability of the treated
waste was relatively low. Permeability values
shown in Table 3-7 ranged from 0.33 x 10'7 to
2.5 x 10"7 cm/sec. For comparison, these values
are of the same order of magnitude as clays used
in the construction of bottom liners for hazard-
ous waste landfills. Table 3-8 summarizes un-
confined compressive strengths (UCS) for the
treated wastes and compares the values to both
EPA minimum recommendations for placement
in a hazardous waste landfill and American
Society for Testing and Materials
(ASTM)/American Concrete Institute (ACI)
standards for concrete. UCS values of the
treated waste ranged from 170 to 720 psi; these
values are above EPA's minimum recommenda-
tion of 50 psi for UCS for stabilized wastes to be
disposed of in a hazardous waste landfill (U.S.
EPA, 1986a). However, these UCS values are
well below the minimum ASTM/ACI standard of
3,000 psi for use in construction of concrete
sidewalks (ASTM, 1991). (STC claims that waste
treated by its technology can be made to meet
requirements for construction applications, if
desired.)
Table 3-9 presents the volume of raw waste
and treated waste for each of the batches ana-
lyzed, along with calculated percent increases.
For each batch the volume of the treated waste
was greater than the volume of the raw waste
due to the addition of STC's proprietary re-
agents. The volume increases for the four
batches ranged from 59 to 75 percent (68 percent
average).
The long-term stabilization and solidification
effectiveness of the STC technology will be
monitored over a 3-year period. Samples of
treated material from the SPT site were analyzed
using the TCLP and TWA tests at 6 and 18
months following the demonstration. In addi-
tion, UCS was analyzed after 18 months. Results
of the first round of TCLP and TWA tests, 6
months after the demonstration, showed higher
average leachate concentrations of arsenic,
chromium, copper, and higher extract concen-
trations of PCP than reported after the initial
28-day sample curing. The long-term results for
arsenic and chromium were, however, still
within federal regulatory threshold levels for
these metals. The 18-month analyses showed
17
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Table 3-7. Summary of Permeability Data
Batch
1
3
4
5
Radges of Permeability (cm/sec)
1.30x 10-7-2.1 x lO'7
0.52 x ID'7 - 2.5 x lO'7
0.49 x 10'7- 1.3 x 10'7
0.33 x 10 7- 1.3x 1C'7
Requirement for Bottom Liners for
Hazardous Waste Landfills (cm/sec)
l.Ox lO'7
Table 3-8. Summary of Unconfined Compressive Strength Data
Batch
1
3
4
5
UCS (as!)
190 - 720
250 - 320
170 - 380
250 - 430
EPA Minimum Recommended
UCS for Placement in a
Hazardous Waste Landfill (psi)
50
Minimum ASTM/ACI
Standard for Concrete (psi)
3,000
Table 3-9. Summary of Volume Increase for STC-Treated Waste
Batch
l
3
4
5
Volume of Raw Waste
(«*)
56
41
42
46
Volume of Treated
Waste (ft3)
90
73
72
77
Percent Increase
59
75
73
66
improved percent reductions for arsenic, averag-
ing 88 percent reduction, and PCP, averaging 96
percent reduction. Chromium and copper con-
centrations in the TCLP-leachates continued to
increase over the 18-month time period. UCS
tests showed an average 71 percent increase in
physical strength for the STC-treated, waste in
18 months. Appendix 6 contains a more detailed
analysis of these results. Additional long-term
(18-month) weathering studies from exposed
monoliths of the STC-treated waste are discussed
in the TER. Final results for the long-term
monitoring, including 36-month chemical,
leaching, and strength tests, will be available
from EPA upon completion of the analyses.
The process equipment used during the
technology evaluation was observed to be me-
chanically reliable. No equipment-related
problems occurred during the 6-day demonstra-
tion. In addition, the process equipment used
during the demonstration was capable of mixing
all components, including the waste material,
into a homogeneous, solidified product, provided
that the pretreatment screening or size reduction
of surface hardpan material down to 0.04-0.08
18
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inch (1-2 mm) diameter was conducted.
3.2 Summary of Case Studies
The following summary of five case studies
provides additional information on the STC
solidification/stabilization treatment technology.
The information available for these case studies
pertains mainly to chemical data obtained from
preliminary treatability studies. Very little
information was provided pertaining to system
performance or costs. Detailed results and
additional discussions are presented in Appendix
C.
Prior to selection of the STC SITE demon-
stration location at SPT, contaminated soils from
the Tacoma Tar Pits, Purity Oil, and Kaiser Steel
facilities were subjected to preliminary pilot-and
bench-scale treatability testing. These soils were
generally contaminated with both organic and
inorganic constituents.
The treatability tests from the Tacoma Tar
Pits facility yielded reductions ranging from 89
to 99 percent for TCLP analyses of cadmium,
copper, nickel, lead, and zinc, with EP Toxicity
percent reductions in excess of 90 percent for
nickel and zinc. Up to 11 of 26 semivolatile
organics, and up to six volatile organics showed
reductions for TCLP analyses. However, the
tests did not include measures to quantify vola-
tiles that may have been lost due to mixing and
curing. The EP Toxicity test yielded reductions
for up to 10 semivolatile organics and up to six
metals. TWA for semivolatiles yielded slight to
moderate reductions for up to 20 of 26 semi-
volatiles analyzed.
STC's immobilization technology yielded
reductions in leachate concentrations for 10 of
12 metals analyzed at the Purity Oil Facility.
Greater than 95 percent reduction was achieved
for TCLP lead and cadmium analyses. Chromi-
um showed percent reductions greater than 56
percent for the TCLP. STC's technology also
yielded reductions in leachate concentrations for
two of eleven volatile organics, and three of six
semivolatile organics based on the TCLP.
However, the tests did not include measures to
quantify volatiles that may have been air-
stripped. Percent reductions for the organic
contaminants naphthalene, phenanthrene, flour-
anthene, 2-methylnaphthalene at the Kaiser
Steel Facility were in excess of 78 percent based
on TWA. Additional studies to determine the
optimum reagent-to-waste ratios for the TCLP
were also performed at the Kaiser Steel and
Purity Oil Facilities.
Treatability results from lead-contaminated
soils at the Brown's Battery Breaking Superfund
SITE near Reading, Pennsylvania indicate stabi-
lization of lead at concentrations up to 53,600
ppm in the samples analyzed; however, because
dilution factors were not reported, contaminant
reduction percentages could not be determined.
Post-treatment verification laboratory results
from the Lion Oil Refinery, El Dorado,
Arkansas, indicate that contaminated refinery
sludge was treated for selected metals, volatile
and semivolatile organics. In all but two cases,
the metals and organics analyzed were below
detection limits for the treated wastes; however
concentrations for the raw waste sludge were not
available for this report. Results for the
solidification of the waste sludge show that the
greatest unconfined compressive strengths were
obtained by using 70 to 80 percent sludge (by
weight) in addition to 7 to 11 percent cement
and 1.4 to 2.4 percent STC proprietary reagents.
3.3 Factors Influencing Performance and
Cost Effectiveness
Several factors can influence the
performance and cost effectiveness of the STC
immobilization technology; remedial project
managers or facility managers should consider
these factors when deciding whether to use the
STC technology. These factors can be grouped
into four main categories: (1) waste characteris-
tics; (2) volume/density increase; (3) operating
conditions; and (4) climate and curing condi-
tions. The following subsections discuss these
categories in detail.
3.3.1 Waste Characteristics
Waste characteristics that may affect the
performance of the STC immobilization technol-
ogy include clay content, coal and lignite con-
tent, moisture content, oil and grease content,
pH of the waste, volatile organic concentrations,
and aggregate size of the waste (STC, 1991).
Wastes with high clay content (>50 percent) may
release clay into the mixing water which may
19
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result in a large concentration of these particles
near the surface of the solidified matrix, pro-
ducing an inferior quality matrix. Coal and
lignite in excess of 1 percent may also impair the
quality of the solidified waste mixture. Wastes
with very high moisture contents should be
treated as sludges and may therefore require
larger amounts of reagents for solidification.
Oil and grease (and other nonpolar organics)
may have deleterious effects on the ability of a
matrix to set, and thus may reduce the uncon-
fined compressive strength of the treated waste.
STC reports that levels of up to 60 percent oil
and grease have been successfully treated
(STC, 1991). Low-pH wastes (e.g., acid sludges)
may react with the relatively higher pH materials
used in the reagent mixture, resulting in
incomplete solidification. Such wastes must be
neutralized prior to treatment.
For wastes with large aggregate sizes,
incomplete mixing may occur which can result
in pockets of untreated waste within an
otherwise homogeneous waste/reagent mixture.
Well-graded raw wastes (i.e., wastes with several
different particle sizes) will form more stable
monolithic blocks than poorly-graded (one-
sized) raw wastes. Additional screening and size
reduction of the SPT contaminated soil
aggregates down to 0.04 - 0.08 inch (1-2 mm)
diameter was also necessary to ensure that
individual aggregates did not bias the chemical
analyses.
Wastes containing volatile organics may
release these organics during the mixing process,
resulting in artificially high percent reductions
for these constituents. In addition, the
concentrations of metals or semivolatile organics
in the waste may impair the ability to meet
desired levels of these constituents in the treated
waste. For example, if the objective of the
treatment is to render waste nonhazardous, the
higher the contaminant concentration in the raw
waste, the higher the concentration in the treated
waste, and even after 90 percent reduction in
TWA or leachate concentrations, the technology
may not be appropriate for some wastes because
the wastes may still be considered hazardous
after treatment.
3.3.2 Volume/Density Increase
Average volume increases of 68 percent were
observed after treatment of the SPT waste. The
volume increase depends on the characteristics of
the waste treated and the desired performance
specifications. The bulk densities of the wastes
increased only 0.6 to 11 percent, with an average
increase of 5.5 percent resulting from the addi-
tion of reagents during treatment. For on-site
disposal, the above volume increases may be
desirable in situations where additional soil
material would be needed for filling-in and
leveling depressions. The increased volume
could reduce the costs of purchasing and trans-
porting fill material to the site. The STC immo-
bilization technology may be less desirable for
use in treating wastes as the ratio of the volume
of the treated waste to the volume of the raw
waste increases. Off-site disposal of treated
wastes becomes more difficult and costly with
increasing volume since disposal costs are usually
on a total weight or unit volume basis.
3.3.3 Operating Conditions
Operating parameters for the STC solidifica-
tion/stabilization treatment process include
mixer power, mixing time, added reagents, and
the additive ratios for the reagents, as shown in
Table 3-1. Any of these operating conditions
can be modified to accommodate differences in
waste characteristics. Operating conditions can
also be modified to yield treated waste better
suited for a particular disposal option or use.
The power delivered to the mixer affects the
degree of mixing of the waste. Wastes that are
exceptionally viscous or that have larger particle
or aggregate sizes may require a larger power
output by the mixer. Remedial project managers
or facility managers should consider the power
output of the mixer when evaluating which
mixer to use to treat a particular waste.
An inordinately long pre-mixing time (4.5
hours) for Batch 4 prior to the addition of the
reagents may have caused the anomalously high
arsenite concentration in the raw waste for this
batch (see Table B-2). Although precise chemi-
cal information necessary to determine the
reactions that took place were not available, ion-
speciation shows that Batch 4 contained greater
quantities of the arsenic ion-species arsenite (HI)
than the other batches analyzed. Reduction from
20
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the more stable arsenate (V) species may have
resulted during the pre-mixing process if at least
one other element was oxidized, thereby balanc-
ing the oxidation/reduction reaction. Such
differences in chemical characteristics of the
waste may be the reason for the very low percent
reduction of arsenic in Batch 4 under acidic
TCLP conditions, since arsenite (III) is more
mobile in acidic soil environments than arsenate
(V) (Dragun, 1988).
The additives ratio for the process can be
varied to account for differences in the compo-
sition of certain wastes. For example, the vol-
ume of water added to the process should be
adjusted to account for the moisture content of
the waste. As mentioned earlier, certain waste
streams with high moisture content may not be
easily treated using solidification/stabilization.
Therefore, the amount of water used in the
treatment process should be decreased with
increasing water content of the waste to be
treated.
3.3.4 Climate and Curing Conditions
The curing temperature and the curing time
will have an effect on the chemical and physical
characteristics of the treated waste. In general,
treated wastes cured at higher temperatures will
cure faster, but the higher temperatures may
enhance organic loss by volatilization. In addi-
tion, the treated waste may not have the equiva-
lent structural integrity to that of wastes cured at
a lower temperature. (An exception to this
would be wastes that are cured at temperatures
at or below freezing.) In general, treated wastes
cured at a constant room temperature will be-
come increasingly stable with increasing time.
Blocks of treated waste that are exposed to the
effects of weather for an extended period of
time may begin to break down as a result of
weather conditions, including precipitation and
freeze/thaw cycles. Solidified wastes should be
allowed to cure for several weeks; ASTM guide-
lines for construction materials require a cure
time of 28 days at 16° to 27°C (ASTM, 1991).
Below-freezing temperatures and heavy rain
could have an adverse impact on the operation of
the STC immobilization technology. If subfreez-
ing temperatures are expected, the mixer and the
water source should be insulated or heated to
avoid freezing of the water used in the process.
Raw materials, including the reagents, should be
protected from precipitation.
3.4 Site Characteristics and Logistics
This section describes the treatment site
characteristics and the logistical requirements for
operating the STC immobilization technology.
The following discussion also addresses site
access; minimum requirements for utilities,
equipment, and supplies; and services necessary
for the STC technology.
3.4.1 Treatment Area
The area selected for application of the STC
immobilization technology should be relatively
level and must be large enough to accommodate
necessary equipment. The area containing the
mixing unit should also be level; it can be paved
or covered with compacted soil or gravel. The
site geotechnical characteristics (e.g., soil bearing
capacity) should be evaluated to identify wheth-
er a foundation is necessary to support the mixer
and ancillary equipment. During the SITE
demonstration, a 35- by 15-foot area was needed
to accommodate the 5-cubic-yard mixer. How-
ever, mixing unit sizes vary from smaller batch
mixers (5 cubic yards) to large pug mill mixers
(15 cubic yards). The treatment area must be
large enough to place other equipment, such as
tanks for the storage of reagents and rinsewater.
A 6- by 10-foot area was needed for personnel
decontamination. The area must also be large
enough to allow for easy movement of large
machinery (e.g., backhoes or bulldozers). In
addition, approximately a 45- by 15-foot area is
required for indoor office and laboratory space.
3.4.2 Site Access
Site access requirements for the treatment
equipment are minimal. The site must be acces-
sible to tractor-trailer trucks. The roadbed must
be able to support such a vehicle for delivery of
the mixer, storage tanks, and the office trailer.
3.4.3 Utilities
The STC immobilization technology requires
water and electricity. Water is used as an addi-
tive in the treatment process and is required for
equipment cleanup and personnel decontamina-
tion. The mixing unit used at the STC SITE
demonstration required 480-volt, 3-phase, 500-
21
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amp electrical service; however, electrical re-
quirements will vary depending upon the type of
mixer used. Additional electrical power (110-
volt, single phase) is required for lighting, and
heating or cooling any office trailer, and operat-
ing any on-site laboratory and office equipment.
A telephone is useful to contact emergency
services and to provide normal communications.
3.4.4 Equipment
The STC immobilization technology requires
several pieces of major and auxiliary equipment
including: a mixer, a bulldozer or a backhoe for
the movement of contaminated material, a
hopper and scale, tanks for the storage of decon-
tamination water, a tank truck, a forklift for
movement of treated waste, a tractor-trailer to
transport heavy equipment, and an office trailer.
In addition, if pretreatment waste aggregate size
reduction is necessary, a screen and a crusher or
shredder would also be required. Miscellaneous
equipment needed would include a dumpster, a
steam or high-pressure cleaner, a gasoline-
powered electric generator if a local power
source is not available, pumps, plastic sheeting,
and personal protective equipment (PPE).
3.4.5 Supplies and Services
A number of supplies are required for appli-
cation of the STC technology. Adequate supplies
of the following are required: the STC
SOILSORB reagents, personal protective
equipment, and drums for the storage of
contaminated materials. Plastic or other
synthetic liners are also necessary to contain
decontamination water until it can be placed in
tanks or other storage. If necessary, receptacles
(e.g., forms) for the treated waste must also be
provided.
Services required on site may include
laboratory services and sanitary facilities.
Analytical equipment may be required on site (or
off site through a contractual arrangement) for
testing of the treated waste for physical
properties or chemical constituents (e.g.,
unconfined compressive strength testing and
TCLP analyses). Sanitation arrangements may
include portable chemical toilets or other
suitable sanitary facilities.
3.4.6 Personal Protective Equipment
The type and amount of PPE required for
persons at sites where the STC immobilization
technology is being used will vary depending on
site conditions and duration of cleanup opera-
tion. Remedial project managers and facility
managers should follow Occupational Safety and
Health Administration (OSHA) and National
Institute for Occupational Safety and Health
(NIOSH) guidelines (or state equivalents) where
appropriate when selecting PPE. Material Safety
Data Sheets (MSDS) recommend the use of
NIOSH-approved respirators, tight fitting gog-
gles, gloves, boots, and clothing to protect the
skin from prolonged contact with the STC chem-
ical reagents P-4 and P-27. The ingredients of
P-4 and P-27 are not listed as containing carcin-
ogens. At a minimum, facility personnel should
always be outfitted in Level D protection.
Where wastes that are being treated by the STC
technology contain volatile organics, volatile
metals, or particulate matter that may present an
inhalation hazard, facility personnel should
upgrade to Level C protection (respirator and
protective clothing) or Level B protection (sup-
plied air and protective clothing) where required.
3.5 Materials Handling Requirements
Materials handling under the STC immobili-
zation technology includes requirements for
handling untreated waste (contaminated soil or
sludge) and treatment product and residuals.
These two categories of wastes are discussed in
detail in the following sections.
3.5.1 Pretreatment Materials Handling
The requirements for materials handling vary
depending upon the type of waste to be treated.
For some wastes, the only pretreatment materials
handling required will be transfer of the con-
taminated material to the mixer. A size reduc-
tion step may be necessary to reduce the particle
size of the waste to a maximum diameter of 3/8
inch to allow for sufficient mixing of the waste
and the treatment reagents. At the SITE demon-
stration, this step was accomplished by forcing
the material through a series of screens; these
screens reduced the particles sizes of the waste to
between 0.04 to 0.08 inch vl to 2 mm) diameter
to ensure that an individual aggregate of un-
treated waste did not bias the chemical analyses.
Other options for size reduction of waste parti-
22
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cles include crushers and grinders. Bench-scale
treatability testing can provide information on
size requirements, but often this can only be
determined in the field. Remedial project
managers and facility managers should investi-
gate possible size reduction requirements prior to
placing wastes into the mixing unit.
3.5.2 Residuals Handling
Several types of residuals are generated as a
result of application of the STC immobilization
technology. These residuals include (1) the
monolithic blocks of treated waste; (2) contam-
inated PPE; (3) process and decontamination
wastewater; and (4) other contaminated materials
(e.g., plastic liners). Requirements for handling
these residuals are discussed below.
The solidified blocks of treated waste may be
handled on site or off site. Solidified wastes
should be allowed to cure for 28 days prior to
ultimate disposal (ASTM, 1991). The solidified
wastes should be shielded from the effects of
precipitation and temperature extremes to the
maximum extent practicable during curing,
including indoor storage or covering with tarps
or plastic sheeting. On- and off-site disposal
options include placement of the blocks in a
landfill provided that appropriate environmental
regulations are met.
Contaminated PPE and other contaminated
debris may also be disposed of either on or off
site. At the SITE demonstration, these materials
were stored in 55-gallon drums until the drums
could be sealed and prepared for disposal. The
materials can then be disposed of in a landfill or
incinerated either on site or off site in accor-
dance with appropriate regulations.
The third class of residuals generated
through use of the STC technology are process
and decontamination wastewaters. Decontami-
nation wastewaters may be recycled back into
the process depending upon their composition.
Decontamination wastewaters that cannot be
reused can be sent off site for treatment or
disposal. If discharge limitations are met and all
necessary permits obtained, decontamination
wastewaters can also be discharged on site into a
sanitary sewer or to a surface water body.
3.6 Personnel Requirements
The STC immobilization technology may be
operated with as few as eight people, but may
involve several more persons depending on
project size and site conditions. Two people
must be skilled in the operation of heavy equip-
ment, such as a bulldozer or backhoe, in order to
move contaminated materials from the area of
contamination to the mixer and to manage the
treated waste. A third person is necessary to
ensure that the proper amount of raw materials
(e.g., reagents) are added to the process. A
fourth person is needed to operate the mixer and
oversee the mixing process. A fifth individual is
required for sampling of the treated waste. A
sixth person must be a trained individual to
conduct air monitoring and to handle health and
safety issues. Finally, two additional people are
necessary: an overall coordinator and an off-site
person to handle administrative requirements.
Although eight persons may be considered as the
minimum the technology can be operated with,
in most cases it may be necessary to have more
persons on site, especially during unusual weath-
er conditions, such as extreme heat or cold, or
when working with Levels B or C personal
protective equipment becomes necessary. A
security guard may also be required.
3.7 Potential Community Exposures
Community exposures to hazardous chemi-
cals from the operation of STC's technology are
expected to be minimal. Potential sources of
community exposure may include particulate and
volatile emissions from the pretreatment screen-
ing, crushing, and mixing processes. Particulate
emissions are generated from the mixing of
waste materials and reagents in the mixer.
Volatile organics may also escape during on-site
excavations and the mixing process if the mixing
is performed in an open-air environment.
Community exposures may be minimized by
placing a tarp over the mixer when it is in oper-
ation.
3.8 Potential Regulatory Requirements
This section discusses environmental, health
and safety, regulatory, and statutory require-
ments that may apply to STC's immobilization
technology. The requirements that apply to
STC's technology may vary depending upon the
23
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location and type of site and the types of wastes
or materials managed at the site.
3.8.1 Resource Conservation and Recovery Act
(RCRA)
Subtitle C of RCRA, as amended by the
Hazardous and Solid Waste Amendments
(HSWA), provides for a comprehensive program
to regulate the treatment, storage, transportation,
and disposal of hazardous wastes. Hazardous
wastes are defined in 40 CFR part 261 as wastes
that are either (1) listed by EPA as hazardous
wastes or (2) exhibit a characteristic of a hazard-
ous waste. The lists of hazardous wastes are
found in 40 CFR part 261, subpart D; the char-
acteristics of hazardous wastes are described in
40 CFR part 261, subpart C.
Persons who generate wastes during the use
of the STC immobilization technology must
determine if the wastes are hazardous. Site
personnel may make this determination by
testing their waste or by using knowledge of the
process generating the waste or knowledge of the
properties of the waste. Wastes that are deemed
hazardous are subject to both general and unit-
specific regulations under RCRA. State regula-
tions may also have additional criteria for the
identification of hazardous wastes.
Raw waste treated using the STC technology
may be classified as a hazardous waste. If the
raw waste is a listed hazardous waste, then
wastes generated from the treatment process
(including the monolithic blocks of treated
waste, decontamination water, contaminated
debris, and contaminated PPE) will, in most
cases, be listed hazardous wastes. If the raw
waste exhibits a characteristic of a hazardous
waste, wastes generated from treatment would
only be hazardous if they continued to exhibit a
characteristic. Residuals generated from the
treatment of characteristic wastes must be evalu-
ated to determine if they exhibit a characteristic
by testing the residuals or using knowledge of
the residuals' composition. In addition, residuals
such as decontamination water can exhibit a
characteristic of a hazardous waste even if the
raw waste does not. The STC immobilization
technology may not be a viable alternative if the
treated waste is still regulated as a hazardous
waste. If the raw waste or treatment residuals
are nonhazardous wastes, certain state regula-
tions may apply to the management of these
wastes.
Under RCRA, certain requirements apply to
the management of hazardous wastes. If hazard-
ous wastes are generated on site, the management
of these wastes must be in accordance with the
requirements of 40 CFR part 262. If the raw
waste is a hazardous waste, the facility would be
required to also comply with the requirement for
hazardous waste treatment, storage, and disposal
facilities (TSDF) in 40 CFR Parts 264 or 265.
Both generators and treaters of hazardous
waste must determine the applicability of the
land disposal restrictions (LDR) to their hazard-
ous wastes. The LDRs are expressed as treat-
ment standards described in 40 CFR part 268,
subpart D or statutory prohibitions in Section
3004(d) of RCRA. Wastes that are prohibited
from land disposal under the LDRs may be land
disposed only if the waste is treated so that
treatment standards are met, or if a variance is
obtained or a no-migration petition is granted.
The STC immobilization technology may not be
a viable treatment alternative if treatment resid-
uals to be placed on the land do not meet LDRs
treatment standards or prohibitions. In general,
materials that are moved from within the bound-
aries of a land disposal unit are not subject to the
LDRs. For example, wastes that are moved from
one cell of a landfill to a different cell in the
same landfill would not be subject to the LDRs,
even though this activity constitutes placement
of hazardous wastes on the land (which is nor-
mally the activity that triggers the LDRs).
However, persons who use the STC technology
should be aware of the potential applicability of
the LDRs to activities associated with the use of
the STC technology.
The treatment, storage, or disposal of haz-
ardous wastes, with certain exceptions, requires
a permit under RCRA (40 CFR 270. l(c)).
Therefore, application of the STC technology at
a site may require a RCRA Subtitle C permit if
the material being treated is a hazardous waste.
However, Section 121(e) of CERCLA may
exempt certain on-site operations associated with
remediations conducted under CERCLA from
RCRA permitting requirements. All facilities
seeking a permit under RCRA are also subject to
the corrective action provisions of Section
3004(u) of RCRA; these provisions are designed
to address releases of hazardous wastes or
hazardous constituents from solid waste manage-
24
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ment units at the facility.
would be expended.
3.8.2 Comprehensive Environmental Re-
sponse, Compensation, and Liability Act
(CERCLA)
CERCLA, as amended by the Superfund
Amendments and Reauthorization Act (SARA),
provides for federal authority to address releases
of hazardous substances. Section 121 of SARA
requires that remedies selected under CERCLA
be protective of human health and the environ-
ment, be cost effective, and utilize permanent
solutions. Section 121 states that remedies that
utilize treatments that reduce the volume, toxici-
ty, and mobility of waste are preferred over
remedies that do not involve such treatment.
Section 121 also mandates that cleanups conduct-
ed under CERCLA authority meet applicable or
relevant and appropriate requirements (ARAR)
under Federal and state statutes. SARA Section
121(d) provides for six waivers from ARARs:
• The remedial action selected is only
part of a total remedial action that
will attain ARARs.
• Compliance with ARARs at the
facility will result in a greater threat
to human health and the environ-
ment than alternative options.
• Compliance with ARARs is techni-
cally impracticable from an engi-
neering perspective.
• The remedial action will achieve a
standard of performance equivalent
to that required under the ARARs
through use of another approach.
• In the case of individual state
ARARs, the state has not
consistently applied the ARARs in
similar circumstances at other
remedial action sites.
• In the case of a remedial action con-
ducted using CERCLA funds under
the authority of Section 104 of
CERCLA, the remedial action
will not provide an amount of
protection to human health and
the environment commensurate
with the amount of money that
In order to meet the requirements of SARA
Section 121, remedial project managers or facili-
ty managers that use the STC immobilization
technology must comply with the substantive
requirements of all ARARs; administrative re-
quirements must only be met for off site actions.
For example, blocks of treated (solidified) wastes
that are disposed of on site must meet the re-
quirements under the LDRs, but would not
require a RCRA Subtitle C permit. Remedial
project managers or facility managers should
refer to EPA's "LDR Guides", July 1989
(OSWER 9347.3-01 FS through 9347.3-06FS), for
guidance concerning applicability of the LDRs
to Superfund sites.
3.8.3 Toxic Substances Control Act (TSCA)
Requirements under the Toxic Substances
Control Act (TSCA) may apply when treating
wastes containing polychlorinated biphenyls
(PCB) using the STC technology. TSCA
regulates the manufacturing, processing,
distribution, and use of items containing PCBs
under the provisions of 40 CFR part 761; subpart
D of part 761 regulates the disposal of PCBs.
Liquid PCB wastes containing at least 50 ppm
PCBs must be disposed of by using a high-
efficiency boiler or an incinerator. Solid PCB
wastes containing at least 50 ppm and less than
or equal to 500 ppm PCBs must be incinerated or
disposed of in a TSCA-approved landfill (40
CFR 761.75). Waste containing PCBs at
concentrations greater than 500 ppm must be
incinerated (40 CFR 761.65).
Sites where spills of PCBs have occurred
after May 4, 1987, must be addressed under the
PCB Spill Cleanup Policy in 40 CFR part 761,
subpart G. In order to meet the requirements
under the spill cleanup policy, wastes slated for
treatment using the STC technology may require
additional treatment, if the PCB spill cleanup
standards are not met. The policy applies to
spills of materials containing 50 ppm or greater
PCBs and establishes cleanup protocols for
addressing such releases based upon the volume
and concentration of the spilled material.
3.8.4 Clean Water Act (CWA)
Requirements under the Clean Water Act
(CWA) will generally apply to direct discharges
25
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to surface waters or discharges to certain waste-
water treatment plants. The CWA established
two programs to regulate the discharge of pollut-
ants into surface water bodies: the National
Pollutant Discharge Elimination System (NPDES)
program established under Section 402 of the
CWA, and the pretreatment program for dis-
charges to Publicly Owned Treatment Works
(POTW) established under Section 307 of the
CWA. The NPDES program establishes a system
under regulations at 40 CFR part 122 to issue
permits that specify effluent limitations for
direct discharges to surface waters. The pre-
treatment program specifies general discharge
prohibitions under regulations in 40 CFR part
403 and industry-specific discharge limitations
in 40 CFR parts 405-699. Although no permits
are required for discharges to a POTW, all
discharge limitations, such as pretreatment
standards established under the CWA, should be
met prior to discharging wastewaters to a POTW.
Local POTWs may also require permits or charge
a fee for discharges to their wastewater treat-
ment systems. Remedial project managers or
facility managers should refer to "CERCLA Site
Discharges to POTW", August 1990
(EPA/540/G-90/005) for further guidance.
Wastewaters from the application of the STC
technology must also be managed in accordance
with any other applicable state and local
discharge requirements that are more stringent
or broader in scope than the NPDES and
pretreatment programs.
3.8.5 Safe Drinking Water Act (SDWA)
The Safe Drinking Water Act (SDWA), as
amended in 1986, includes the following pro-
grams: (1) drinking water standards, (2) under-
ground injection control (UIC) program, and
(3) sole-source aquifer and wellhead protection
programs. Remedial project managers or facility
managers should consider SDWA standards if
wastewaters are being injected into the ground
or if discharge is into an aquifer or surface
water body used for drinking water. Under-
ground injection of hazardous wastes into or
above an underground source of drinking water
is prohibited. Requirements under the SDWA
may also be a concern if wastes from the STC
process are placed in the ground. Decision-
makers considering on-site disposal of residuals
will have to consider local aquifer use and the
potential for release of hazardous substances
from the treated wastes into surface water and
ground water.
3.8.6 Clean Air Act (CAA)
The Clean Air Act (CAA) provided EPA
with the authority to establish emissions stan-
dards for hazardous air pollutants. Under the
CAA, certain stationary sources of air pollutants
are required to monitor for and, in some cases,
restrict air emissions of hazardous air pollutants.
Emissions from the STC solidification/stabiliza-
tion treatment process are not likely to be regu-
lated under the CAA, since the mixing unit is
not likely to be classified as a major stationary
source under the CAA under 40 CFR part 52.
Emissions from the STC treatment process
typically include fugitive dust emissions as well
as volatile organic compound (VOC) emissions
and may be regulated under state or local re-
quirements. State or local permits may be re-
quired if the site is not a site being remediated
under CERCLA authorities. Emissions from the
STC treatment process should be monitored, as
necessary, to ensure compliance with applicable
regulations or permit conditions.
3.8.7 Atomic Energy Act (AEA)
Remedial project managers or facility man-
agers considering use of the STC immobilization
technology may need to comply with regulations
under the Atomic Energy Act (AEA) if raw
waste contains materials defined as source,
special, or byproduct nuclear materials. Regula-
tions under 10 CFR part 20 require monitoring
of radioactive exposure to individuals, marking
of radioactive areas, labelling of radioactive
materials, and disposal and recordkeeping re-
quirements. Regulations under 10 CFR part 30
detail Nuclear Regulatory Commission (NRC)
licensing requirements for the handling of radio-
active materials. Specific licensing requirements
for source materials are found under 10 CFR
part 40. A license may also be required, under
10 CFR part 61, for the land disposal of certain
radioactive wastes. The management of special
nuclear materials may also require a license
under the provisions of 10 CFR part 70.
Additional requirements may be applicable
to the treatment of radioactive wastes at U.S.
Department of Energy (DOE) facilities. The
DOE issues internal orders to their individual
facilities; these orders have the same weight as
26
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regulations at these facilities. These DOE orders
address exposure limits for the public, concen-
trations of radioactivity in soil and water, and
management of radioactive wastes.
EPA also has developed standards for the
management of radioactive materials under the
AEA. Forty CFR part 191 contains require-
ments for the management and disposal of high-
level and transuranic wastes. Regulations for
cleanup, control, and waste disposal at uranium
and thorium mill tailing sites are found in 40
CFR part 192.
3.8.8 Occupational Safety and Health Act
The Occupational Safety and Health Admin-
istration (OSHA) administers standards for the
protection of workers from exposure to hazard-
ous chemicals; certain chemicals used in STC's
reagent are classified as hazardous chemicals.
OSHA regulations applicable to sites where the
STC technology is used may include a require-
ment to develop a written hazard communication
program (HCP) under 29 CFR 1910.1200. The
HCP requires that remedial project managers or
facility managers institute a program to train
employees on the hazards of chemicals on site,
and requires that Material Safety Data Sheets
(MSDS) be available to employees.
OSHA regulations require a variety of ac-
tions for worker protection in 29 CFR parts 1900
to 1926. Section 1910.120 requires that persons
involved in work at hazardous waste sites (de-
fined as RCRA-permitted and interim status
facilities, RCRA corrective action sites, and sites
where removal and remedial actions are conduct-
ed under CERCLA authorities) undergo a 40-
hour health and safety training course and
medical surveillance. The training and medical
surveillance applies to all persons involved in the
STC treatment process, as discussed previously.
Regulations in 40 CFR 1910.120 also require the
remedial project manager or facility manager to
prepare a site health and safety plan, provide
PPE for employees, perform air monitoring at
the site, and develop decontamination proce-
dures.
27
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Section 4.0
Economic Analysis
One of the goals of SITE is to develop reli-
able cost data for unique and commercially
available hazardous waste treatment technolo-
gies. The purpose of this section is to provide
information that will allow the remedial project
manager or facility manager to develop site-
specific costs associated with the use of the STC
immobilization technology.
A cost analysis of the STC immobilization
technology to treat 15,000 cubic yards of con-
taminated soil was evaluated using two sizes of
mixers (5 and 15 cubic yards) and two different
mixing times (1/2 hour and 1 hour) per batch.
This analysis revealed a range of costs from $190
to $330 per cubic yard of raw waste depending
on the size of the mixer and the duration of
mixing. Supplies and consumables were the
largest cost in the demonstration, ranging from
47 to 81 percent of the total cost. The reagent
cost to treat a cubic yard of waste ranged from
$80 to $153 depending on the initial total organic
content of the waste. Processing costs ranged
from approximately $40 to $175 per cubic yard
of waste. Labor costs (9 to 30 percent of the
total cost) and analytical expenses (4 to 12 per-
cent of the total cost) were also significant. This
section describes the assumptions made and
procedures used in determining the technology
costs.
4.1 Assumptions
The major assumptions used to evaluate the
cost of the STC immobilization technology are
based on information provided by STC, or from
the actual costs incurred in conducting the SITE
demonstration. Certain assumptions were made
to account for variable site and waste parameters
as well as the nonrepresentative nature of the
cost of the demonstration on a waste-unit basis.
Some of the assumptions will undoubtedly have
to be refined to reflect site-specific conditions.
4.1.1 Waste Volume and Site Size
For the purposes of this analysis, the waste
volume is assumed to be 15,000 cubic yards
(approximately 18,800 tons) of contaminated
soils. It is also assumed that contamination on
average extends to a depth of 3 feet from the
surface and covers an area of 3 acres (130,680
square feet).
4.1.2 Major Technology Design and Perfor-
mance Factors
For the purpose of this analysis, it was
assumed that the STC immobilization technology
is a batch operation conducted in mixers de-
signed to treat either 5 cubic yards or 15 cubic
yards of contaminated soils per batch. This
analysis was conducted for both mixer capacities
using mixing times of one-half hour per batch
and one hour per batch; allowing 5 minutes to
load contaminated soils and reagents per batch,
and 5 minutes to unload the treated wastes. The
mixing time of 1/2 hour represents an optimistic
assessment that the entire mixing operation for a
batch will be completed in 1/2 hour. The 1-
hour mixing time represents a more realistic
estimate of the time needed for the entire mixing
operation per batch. It was also assumed that the
mixer will be operated 5 days per week for 8
hours per day. Table 4-1 shows the resulting
throughputs and project duration times to reme-
diate the 15,000 cubic-yard site.
4.1.3 Costs Sensitive to Specific Waste/Site
Conditions
The cost of the STC treatment process may
be affected by variations in waste type or site
conditions. In general, the longer it takes to
prepare wastes for mixing, the more expensive
the STC process becomes. Factors that may
increase the cost include raw waste pretreatment
29
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Table 4-1. STC Technology Design and Performance Factors
Option
1
2
3
4
Mixer Capacity
(yd*)
5
5
15
15
Mixing Time
(h*)
1.0
0.5
1.0
0.5
Throughput
(yds/week)
200
400
600
1,200
Duration
(mouths)
18
9
6
3
requirements (e.g., screening and size reduction),
difficulty of excavation for on site actions,
distance from the raw waste to the mixer, and
availability of utilities. For the purposes of this
analysis, however, it has been assumed that
mixing accounts for the vast majority of time
spent during the STC treatment process, and that
the time spent preparing for the mixing process
is negligible. (That is, preparing for treatment
processing will be conducted while other batches
are being mixed.)
4.1.4 Financial Assumptions
For the purposes of this analysis, it is as-
sumed that financial factors (such as deprecia-
tion on non-capital equipment, interest rates,
and nonprocess utility costs) will have a negligi-
ble effect on total treatment costs. This assump-
tion is based on the following:
• The STC mixer will likely have little
or no salvage value at the end of its
life cycle.
• Depreciation of auxiliary support
equipment (backhoes and forklifts)
will be included in the cost of rent-
ing.
• Depreciation of purchased non-capi-
tal equipment will be negligible
compared to the full cost of the
remediation.
• Compared to total site remediation
costs, the loss of present value for
working capital and contingency
costs will be negligible. Therefore,
interest rates will not be addressed.
4.2 Itemized Costs
Table 4-2 compares the cost estimates for the
STC immobilization technology, using the four
options described in Section 4.1.2. The itemized
costs include treatment costs only, and are
further described below and summarized in
Table 4-3 which follows Section 4.2.9.
Nontreatment costs including permitting and
regulatory costs, performance bonds, insurance,
and transport or disposal costs for residuals,
PPE, and the treated waste are not included in
cost estimates for the STC technology.
4.2.1 Site Preparation Costs
Site preparation costs include site design,
surveys, legal searches, access rights, preparation
for support facilities and auxiliary equipment
and other site-related costs. These preparation
costs, exclusive of site development, are assumed
to equal 500 staff hours at $50/hour.
4.2.2 Equipment Costs
Equipment costs are divided into two
categories: (1) major equipment costs and (2)
auxiliary equipment costs. These costs are
discussed in the following subsections.
4.2.2.1 Major Equipment Costs
According to STC, the capital cost of a 5-
cubic-yard capacity mixer is $50,000 and the
cost of a 15-cubic-yard mixer is $150,000.
Using straight-line depreciation and assuming a
3-year life cycle, a straight-line depreciation of
$16,667 per year for the 5-cubic-yard mixer and
$50,000 per year for the 15-cubic-yard mixer is
assumed for purposes of this analysis.
30
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Table 4-2. STC Technology Cost Comparison
Cost Items
Site preparation
Equipment
Start-Up
Supplies and
Consumables
Labor
Utilities
Analytical
Maintenance
Site Demobilization
Total Cost
Options
1
$25,000
$365,500
$51,800
$2,298,375
$1,479,820
$86,250
$587,813
$7,500
$11,250
$4,913,308
2
$25,000
$182,750
$51,800
$2,298,375
$749,684
$48,450
$297,825
$3,750
$11,250
$3,668,884
3
$25,000
$138,500
$51,800
$2,298,375
$496,260
$37,500
$195,938
$7,500
$11,250
$3,262,123
4 :
$25,000
$69,250
$51,800
$2,298,375
$257,904
$24,317
$101,888
$3,750
$11,250
$2,843,534
4.2.2.2 Auxiliary Equipment Costs
Auxiliary equipment includes such items as
a support trailer or decontamination equipment
that do not fall under the category of capital
equipment costs. For example, although a
backhoe is considered a major equipment item,
it will not be considered a piece of capital
equipment for this analysis.
Auxiliary equipment items may be divided
into two categories: rental and purchased
equipment. Because of the high cost of
purchasing and transporting construction
equipment, it will be assumed that this
equipment is rented locally, near the site. Based
on previous SITE demonstrations, the following
rental equipment costs are assumed:
• Site trailer
$400/month
Earth-moving equipment $5,325/month
(backhoe and loader)
• Wastewater tank
• Forklift
$300/month
$l,950/month
• Tank truck
• Scale
$2,000/month
$l,200/month
Purchased equipment includes miscellaneous
expendable materials (such as 55-gallon drums),
and equipment that would be cheaper to buy
than to rent. For instance, a steam cleaner,
electric generator, and all necessary
decontamination supplies (including fuel to run
the generator) may be purchased for $6,500.
The life cycles of the generator and steam
cleaner are assumed to be 1 year; for Option 1, it
would be necessary to buy these items twice. It
is assumed that this equipment will be used on
other projects during its life cycle. Auxiliary
purchased equipment costs are as follows:
• Miscellaneous equipment $3,200/month
(Dumpster, sludge pumps,
plastic sheets, 55-gallon drums)
Personal protective
equipment (Disposable
boots, gloves, protective
clothing, etc.)
$4,000/month
Decontamination $6,500/year
equipment (Steam cleaner,
generator, fluids)
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4.2.3 Startup Costs
The startup cost, including moving all equip-
ment to the site, on-site mobilization, equipment
setup, and preliminary chemical and leaching
tests of raw waste, is estimated to be $51,800.
Of this amount, $46,800 is for preliminary
analytical costs including TCLP and TWA.
4.2.4 Supplies and Consumables
The cost for materials is as follows:
• P4 Reagent
• P27 Reagent
$600/ton
$225/ton
An average of 270 Ibs of P4 Reagent and 642
Ibs of P27 Reagent were used for every cubic
yard of waste processed during the STC demon-
stration. This corresponds to a total cost of
$2,298,375 for reagents used in the demonstra-
tion to remediate a 15,000 cubic-yard site.
However, because the waste treated during the
STC demonstration contained high organic
concentrations (e.g., pentachlorophenol), greater
quantities of the costlier P4 Reagent were re-
quired. According to STC, wastes with negligi-
ble organic concentrations (i.e., less than 500
ppm total organics), may require as little as 25
Ibs of P4 Reagent for every cubic yard of raw
waste treated; this would result in a total cost of
$1,195,875 for reagents.
In addition, it is assumed that a 3-month
supply of consumables and maintenance materi-
als represents 10 percent of the cost of mainte-
nance or 1 percent of the cost of major equip-
ment ($50,000) per quarter year.
4.2.5 Labor
Based on the SITE demonstration conducted
using STC's immobilization technology, eight
people from STC per day are assumed to be
required to accomplish the remedial action: two
to operate the treatment process equipment; five
to provide support in the field (such as waste
collection); and one to provide off-site support
such as data tabulation, reporting and adminis-
trative requirements. The two treatment process
personnel include a process operator and coordi-
nator. Field support personnel will operate soil-
moving equipment (backhoe and forklift),
coordinate site health and safety, and collect
samples. This analysis assumes that the seven
process and field support personnel will receive
a per diem in addition to regular compensation.
Off-site support personnel receive no per diem.
Because it will take an estimated 3 to 18 months
to remediate a 15,000-cubic-yard site, the job
may involve local hires to reduce transportation
costs. This analysis allows for round trips home
(one per month) for the seven on-site staff,
including the initial and final travel to and from
the site.
As described above, eight people per day are
required for the remediation. Labor costs are
based on a 40-hour week and are assumed to be
$40 per hour, including overhead and fringe
benefits. In addition, seven of the eight people
will receive a per diem of $80 per day to cover
the costs of meals and lodging. Since STC envi-
sions that its on-site people will be housed near
the site, this per diem will apply for 28 days
each month. Each on-site person will be allowed
one weekend of paid "home leave" per month,
costing $500 in transportation per on-site person.
An after-hours security service is assumed to
cost $21 per hour for 108 hours per week
(12 hours per weeknight plus the weekend).
Health and safety training costs incurred by STC
are not included in this cost estimate. Process
and field support training, however, is assumed
to be of 16 hours duration per field staff.
4.2.6 Utilities
Water is used in the waste treatment process
and for decontamination at rates ranging from
approximately 30,000 to 154,000 gallons per
week depending on the daily throughput as
indicated in Options 1 through 4, and assuming
from the STC SITE demonstration that water
equal to 42 percent of the raw waste is added in
the process. Approximately 5,000 gal/wk are
assumed necessary for decontamination. Total
water usage may vary by as much as 25,000
gal/wk as a result of site and waste variations,
specifically moisture content of the raw waste.
The cost of water brought to the site in trucks is
assumed by STC to be $5 per thousand gallons.
Diesel fuel, approximately 25 gallons per
hour, is needed to run the STC process, using the
5-cubic-yard mixer, as well as supporting
equipment. Fuel costs (at $1.00/gal, 25 gal/hr)
amount to $25.00/hour or $l,000/week,
32
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assuming continuous operation 8 hours/day,
5 days a week. Total fuel costs using the 15-
cubic-yard mixer are estimated to be
approximately $27.50/hour or $l,100/week.
The cost of telephone and electricity is
assumed to be negligible. The cost of these
nonfuel utilities is not likely to average more
than $5 per day after mobilization depending on
climate. (Electricity for the steam cleaner is
assumed to be provided by a portable generator
run on diesel fuel, and is included in the diesel
fuel cost).
4.2.7 Analytical Costs
There are two phases of sampling involved
with the STC solidification/stabilization treat-
ment process. The first phase of sampling is of
the raw waste using TCLP results to determine if
the waste is classified as a hazardous waste. The
second phase involves sampling the treated
waste. For this phase, it is assumed that three
tests will be conducted on the treated waste:
Toxicity Characteristic Leaching Procedure
(TCLP), total waste analysis (TWA), and analysis
for unconfined compressive strength (UCS).
The TCLP analysis will be performed to deter-
mine if the treated waste is hazardous, and also
to evaluate the effectiveness of treatment with
respect to inorganics as required by the land
disposal restrictions under RCRA. Likewise,
TWA results will be used to assess the perfor-
mance of the technology with respect to organics
as required by the land disposal restrictions.
Finally, UCS testing will be used to evaluate the
structural integrity of the treated waste. Costs
for data tabulation and sampling personnel have
been included as labor costs.
This analysis assumes that one raw waste
sample will be collected every other day. Nor-
mally, a full TCLP scan for metals, volatile
organic compounds, and semivolatile organic
compounds would cost approximately $1,100 per
sample. However, an alternative "targeted"
analysis for site-specific hazardous constituents
of concern is assumed to be $300 per sample. In
addition, quality assurance/quality control
(QA/QC) samples will be collected; for the
purpose of this analysis; the analytical cost of
these samples is assumed to equal 25 percent of
the total cost of the original analysis.
For sampling of treated waste, it is assumed
that 5 percent of the batches will be sampled.
Since the throughput rate for the process is 40
batches per week (Options 1 and 3) or 80 batches
per week (Options 2 and 4), two treated waste
samples will be collected per week for Options
1 and 3, and four treated waste samples will be
collected per week for Options 2 and 4. As with
the raw waste, the costs for a targeted TCLP
analysis of the treated waste is assumed to be
$300 per sample. The costs for TWA of metals
is assumed to be $110 per sample. The cost for
testing the treated waste for UCS is assumed to
be $50 per sample. As with the raw waste, the
costs for QA/QC sampling are assumed to equal
25 percent of the total cost of the original analy-
sis.
4.2.8 Maintenance Costs
Maintenance costs, including repair and
replacement costs, are assumed to be 10 percent
of annual major equipment costs. The cost of
major equipment (i.e., the mixer) is assumed to
be $50,000 for Options 1 and 2, and $150,000 for
Options 3 and 4.
4.2.9 Site Demobilization
The cost for site demobilization includes
labor costs for final decontamination and remov-
al of equipment, site cleanup and restoration, as
well as any necessary run-on/run-off or erosion
control measures. Disposal costs for residuals,
equipment rinsate and decontamination solution,
and PPE are considered nontreatment costs and
are not included as site demobilization costs.
33
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Table 4-3. Summary of Itemized Costs
Option 1 (18 months)
Site Preparation
Subtotal $25,000
/
Equipment
Major Equipment
Mixer ($50,000/36 mo)(18 mo) $25,000
Auxiliary Equipment
Site Trailer ($400/mo)(18 mo) 7,200
Backhoe & Loader ($5,325/mo)(l8 mo) 95,850
Waste water Tank ($300/mo)(18 mo) 5,400
Forklift ($ 1,950/mo)( 18 mo) 35,100
Tank Truck ($2,000/mo)(18 mo) 36,000
Scale ($ 1,200/mo)( 18 mo) 21,600
Miscellaneous Equipment
(Dumpster, pumps, plastic sheeting,
55-gallon drums)($3,200/mo)(18 mo) 57,600
Personal protective Equipment
Disposable boots, gloves,
protective clothing, etc.)
($4,000/mo)(18 mo) 72,000
Decontamination Equipment (steam cleaner,
generator, fluids)
($6,500/12 mo)(18 mo) 9.750
Subtotal $365,500
Startup
Miscellaneous Mobilization $5,000
Preliminary Analytical
TWA (24 samples)($ 1,200/sample) 28,800
TCLP (24 samples)($750/sample) 18.000
Subtotal $51,800
Supplies and Consumables
P4 Reagent (2,025 tons)($600/ton) $1,215,000
P27 Reagent (4,815 tons)($225/ton) 1.083.375
Subtotal $2,298,375
34
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Table 4-3. Summary of Itemized Costs (Continued)
Labor
Process Operators (2)($40/hr)(40 hr/wk)(75 wk)
Field Support (5)($40/hr)(40 hr/wk)(75 wk)
Off-Site Support (l)($40/hr)(40 hr/wk)(75 wk)
Security (l)($21/hr)(108 hr/wk)(75 wk)
Per Diem (7)($80/day)(28 day/mo)(18 mo)
Home Leave (7)($500/mo)(18 mo)
Training (7)($40/hr)(16 hr)
Utilities
Fuel ($l/gal)( 1,000 gal/wk)(75 wk)
Water ($5/1,000 gal)(30,000 gal/wk)(75 wk)
Analytical
Pretreatment
(TCLP) (2.5 samples/wk)($300/sample)(75 wk)
Posttreatment
(TCLP) (12 samples/wk)($300/sample)(75 wk)
(TWA) (12 samples/wk)($ 110/sample)(75 wk)
(UCS) (12 samples/wk)($50/sample)(75 wk)
QA/QC ($470,250)(0.25)
Maintenance
($5,000/yr)(].5yr)
Site Demobilization
Labor (225 hr)($50/hr)
Subtotal
Subtotal
Subtotal
Subtotal
Subtotal
$240,000
600,000
120,000
170,100
282,240
63,000
4.480
$75,000
11.250
$56,250
270,000
99,000
45,000
117.563
$ 7.500
$ 11.250
$1,479,820
$86,250
$587,813
$7,500
$ 11.250
Total (Option 1)
$4,913,308
35
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Table 4-3. Summary of Itemized Costs (Continued)
Option 2 (9 months)
Site Preparation
Subtotal $25,000
Equipment
Major Equipment
Mixer ($50,000/36 mo)(9 mo) $12,500
Auxiliary Equipment
Site Trailer ($400/mo)(9 mo) 3,600
Backhoe & Loader ($5,325/mo)(9 mo) 47,925
Wastewater Tank ($300/mo)(9 mo) 2,700
Forklift ($l,950/mo)(9 mo) 17,550
Tank Truck ($2,000/mo)(9 mo) 18,000
Scale ($ 1,200/mo)(9 mo) 10,800
Miscellaneous Equipment
(Dumpster, pumps, plastic sheeting,
55-gallon drums)($3,200/mo)(9 mo) 28,800
Personal protective Equipment
Disposable boots, gloves,
protective clothing, etc.)
($4,000/mo)(9 mo) 36,000
Decontamination Equipment (steam cleaner,
generator, fluids)
($6,500/12 mo)(9 mo) 4.875
Subtotal $182,750
Startup
Miscellaneous Mobilization $5,000
Preliminary Analytical
TWA (24 samples)($l,200/sample) 28,800
TCLP (24 samples)($750/sample) 18.000
Subtotal $51,800
Supplies and Consumables
P4 Reagent (2,025 tons)($600/ton) $1,215,000
P27 Reagent (4,815 tons)($225/ton) 1.083.375
Subtotal $2,298,375
36
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Table 4-3. Summary of Itemized Costs (Continued)
Labor
Process Operators (2)($40/hr)(40 hr/wk)(38 wk)
Field Support (5)($40/hr)(40 hr/wk)(38 wk)
Off-Site Support (l)($40/hr)(40 hr/wk)(38 wk)
Security (l)($21/hr)(108 hr/wk)(38 wk)
Per Diem (7)($80/day)(28 day/mo)(9 mo)
Home Leave (7)($500/mo)(9 mo)
Training (7)($40/hr)(16 hr)
Utilities
Fuel ($l/gal)( 1,000 gal/wk)(38 wk)
Water ($5/1,000 gal)(55,000 gal/wk)(38 wk)
Subtotal
Subtotal
$121,600
304,000
60,800
86,184
141,120
31,500
4.480
$38,000
10.450
$749,684
$48,450
Analytical
Pretreatment
(TCLP) (2.5 samples/wk)($300/sample)(38 wk)
Posttreatment
(TCLP) (12 samples/wk)($300/sample)(38 wk)
(TWA) (12 samples/wk)($ 110/sample)(38 wk)
(UCS) (12 samples/wk)($50/sample)(38 wk)
QA/QC ($238,260)(0.25)
Maintenance
($5,000/yr)(0.75 yr)
Site Demobilization
Labor (225 hr)($50/hr)
Subtotal
$28,500
136,800
50,160
22,800
59.565
$297,825
$ 3.750
Subtotal $3,750
$ 11.250
Subtotal $ 11.250
Total (Option 2)
$3,668,884
37
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Table 4-3. Summary of Itemized Costs (Continued)
Option 3 (6 months)
Site Preparation
Subtotal $25,000
Equipment
Major Equipment
Mixer ($150,000/36 mo)(6 mo) $25,000
Auxiliary Equipment
Site Trailer ($400/mo)(6 mo) 2,400
Backhoe & Loader ($5,325/mo)(6 mo) 31,950
Wastewater Tank ($300/mo)(6 mo) 1,800
Forklift ($ 1,950/mo)(6 mo) 11,700
Tank Truck ($2,000/mo)(6 mo) 12,000
Scale ($l,200/mo)(6 mo) 7,200
Miscellaneous Equipment
(Dumpster, pumps, plastic sheeting,
55-gallon drums)($3,200/mo)(6 mo) 19,200
Personal protective Equipment
Disposable boots, gloves,
protective clothing, etc.)
($4,000/mo)(6 mo) 24,000
Decontamination Equipment (steam cleaner,
generator, fluids)
($6,500/12 mo)(6 mo) 3.250
Subtotal $138,500
Startup
Miscellaneous Mobilization $5,000
Preliminary Analytical
TWA (24 samples)($l,200/sample) 28,800
TCLP (24 samples)($750/sample) 18.000
Subtotal $51,800
Supplies and Consumables
P4 Reagent (2,025 tons)($600/ton) $1,215,000
P27 Reagent (4,815 tons)($225/ton) 1.083.375
Subtotal $2,298,375
38
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Table 4-3. Summary of Itemized Costs (Continued)
Labor
Process Operators (2)($40/hr)(40 hr/wk)(25 wk)
Field Support (5)($40/hr)(40 hr/wk)(25 wk)
Off-Site Support (l)($40/hr)(40 hr/wk)(25 wk)
Security (l)($21/hr)(l08 hr/wk)(25 wk)
Per Diem (7)($80/day)(28 day/mo)(6 mo)
Home Leave (7)($500/mo)(6 mo)
Training (7)($40/hr)(16 hr)
Utilities
Fuel ($l/gal)( 1,000 gal/wk)(25 wk)
Water ($5/1,000 gal)(80,000 gal/wk)(25 wk)
Analytical
Pretreatment
(TCLP) (2.5 samples/wk)($300/sample)(25 wk)
Posttreatment
(TCLP) (12 samples/wk)($300/sample)(25 wk)
(TWA) (12 samples/wk)($ 110/sample)(25 wk)
(UCS) (12 samples/wk)($50/sample)(25 wk)
QA/QC ($470,250)(0.25)
Maintenance
($15,000/yr)(0.5 yr)
Site Demobilization
Labor (225 hr)($50/hr)
Subtotal
Subtotal
Subtotal
$80,000
200,000
40,000
56,700
94,080
21,000
4.480
$27,500
10.000
$18,750
90,000
33,000
15,000
39.188
$496,260
$37,500
$195,938
$ 7.500
Subtotal $7,500
$ 11.250
Subtotal $ 11.250
Total (Option 3)
$3,262,123
39
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Table 4-3. Summary of Itemized Costs (Continued)
Option 4 (3 months)
Site Preparation
Subtotal $25,000
Equipment
Major Equipment
Mixer ($ 150,000/36 mo)(3 mo) $ 12,500
Auxiliary Equipment
Site Trailer ($400/mo)(3 mo) 1,200
Backhoe & Loader ($5,325/mo)(3 mo) 15,975
Wastewater Tank ($300/mo)(3 mo) 900
Forklift ($1,950/mo)(3 mo) 5,850
Tank Truck ($2,000/mo)(3 mo) 6,000
Scale ($l,200/mo)(3 mo) 3,600
Miscellaneous Equipment
(Dumpster, pumps, plastic sheeting,
55-gallon drums)($3,200/mo)(3 mo) 9,600
Personal Protective Equipment
Disposable boots, gloves,
protective clothing, etc.)
($4,000/mo)(3 mo) 12,000
Decontamination Equipment (steam cleaner,
generator, fluids)
($6,500/12 mo)(3 mo) 1.625
Subtotal $69,250
Startup
Miscellaneous Mobilization $5,000
Preliminary Analytical
TWA (24 samples)($l,200/sample) 28,800
TCLP (24 samples)($750/sample) 18.000
Subtotal $51,800
Supplies and Consumables
P4 Reagent (2,025 tons)($600/ton) $1,215,000
P27 Reagent (4,815 tons)($225/ton) 1.083.375
Subtotal $2,298,375
40
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Table 4-3. Summary of Itemized Costs (Continued)
Labor
Process Operators (2)($40/hr)(40 hr/wk)(13 wk)
Field Support (5)($40/hr)(40 hr/wk)(13 wk)
Off-Site Support (l)($40/hr)(40 hr/wk)(13 wk)
Security (l)($21/hr)(108 hr/wk)(13 wk)
Per Diem (7)($80/day)(28 day/mo)(3 mo)
Home Leave (7)($500/mo)(3 mo)
Training (7)($40/hr)(16 hr)
Utilities
Fuel ($l/gal)( 1,000 gal/wk)(13 wk)
Water ($5/1,000 gal)( 154,000 gal/wk)(13 wk)
Analytical
Pretreatment
(TCLP) (2.5 samples/wk)($300/sample)( 13 wk)
Posttreatment
(TCLP) (12 samples/wk)($300/sample)( 13 wk)
(TWA) (12 samples/wk)($110/sample)( 13 wk)
(UCS) (12 samples/wk)($50/sample)( 13 wk)
QA/QC ($470,250)(0.25)
Maintenance
($15,000/yr)(0.25 yr)
Site Demobilization
Labor (225 hr)($50/hr)
Subtotal
Subtotal
Subtotal
$41,600
104,000
20,800
29,484
47,040
10,500
4.480
$14,300
10.017
$9,750
46,800
17,160
7,800
20.378
$257,904
$24,317
$101,888
$ 3.750
Subtotal $3,750
$ 11.250
Subtotal $ 11.250
Total (Option 4)
$2,843,534
41
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Table 4-3. Summary of Itemized Costs (Continued)
Note: These figures correspond to the following approximate costs per cubic yard of raw waste,
for each option, assuming on-site in-place disposal:
• Option 1 $330
• Option 2 $245
• Option 3 $220
• Option 4 $190
Off-site transport and disposal could significantly increase these costs.
Additionally, the lower the organic concentrations in the raw waste, the less P4 Reagent
is needed. If the raw waste contains negligible organic concentrations (less than 500 ppm
total organics), as little as 1 percent by weight P4 Reagent would be needed. This would
result in the following costs per cubic yard of raw waste for each option:
• Option 1 $255
• Option 2 $170
• Option 3 $145
• Option 4 $120
42
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Section 5.0
References
American Nuclear Society, 1986. Measurement
of the Leachability of Solidified Low-Level
Radioactive Wastes by a Short-Term Test
Procedure, ANS 16.1.
American Society for Testing and Materials,
1991. Annual Book of ASTM Standards.
ASTM Philadelphia, PA.
COM Federal Programs Corporation, 1989. Pre-
Remedial Design Soil Boring Report for the
Selma Pressure Treating Site, Selma,
California.
Dragun, J., 1988, The Soil Chemistry of
Hazardous Materials. Hazardous Materials
Control Research Institute, Maryland.
STC, 1991. Personal Communication with Greg
Maupin, STC.
U.S. EPA, 1986a. Prohibition on the Disposal of
Bulk Liquid Hazardous Waste in Landfills -
Statutory Interpretive Guidance.
EPA/530/SW86/016.
U.S. EPA, 1986b. Test Methods for Evaluating
Solid Waste, Volumes IA and II, Third
Edition, EPA Document Control Number
955-001-00000-1.
U.S. EPA, 1990a. STC SITE Program Demon-
stration Plan, Volume I: Draft Test Plan,
October.
U.S. EPA, 1990b. STC SITE Program Demon-
stration Plan, Volume III: Quality Assurance
Project Plan, November.
43
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Appendix A
Vendor's Claims for the Technology
-------
Appendix A
Table of Contents
Pace
Introduction 47
STC's Immobilization Technology 47
Applications of the STC Technology 48
Summary 48
References 48
List of Figures
Figure Page
A-1 Contaminated Soil Process Flow Diagram 49
46
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Appendix A
Vendor's Claims for the Technology
Introduction
Traditionally, organic sludges and
contaminated soils have been solidified through
the use of lime, kiln dust, fly ash, and Portland
cement. These low-technology methods have a
common approach: the organic waste being
treated is detained in a solidified mass without
being truly stabilized insofar as leaching is
concerned. In addition, these traditional
approaches require voluminous amounts of
pozzolonic materials in order to increase the
strength of the treated material for its ultimate
use in landfills. The end result yields a treated
waste product that is 2 to 3 times larger than the
original waste volume, thereby creating high
waste mixing, transporting, and disposal costs.
These costs substantially reduce the benefits of
utilizing inexpensive pozzolans.
During the last 10 years, various innovative
immobilization technologies have been
developed with the intention of significantly
reducing the extractable concentration of organic
and/or inorganic constituents, including
difficult-to-stabilize inorganic contaminants
such as arsenic, hydrogen cyanide, and
hexavalent chromium. These innovative
immobilization technologies have involved the
use of surface-modified agents (such as clays),
surfactants, and other reagents (such as silicates)
to stabilize waste constituents in conjunction
with solidification.
The STC technology for contaminant
immobilization involves stabilization of the
waste's organic and inorganic components to
decrease teachability and lower the interference
of the component contaminants with the
solidification/stabilization matrix. This
immobilization is followed by bonding and
microencapsulation of the waste in a solid
silicate matrix in order to yield adequate
physical strength and further reduce leachability.
The final immobilization treatment steps are
accomplished by ambient temperature mixing of
STC treatment reagents, utilized in either dry
form or as a slurry.
The STC immobilization technology has been
used, in conjunction with the proper materials
handling equipment, for various soils and sludges
to remediate complex hazardous waste sites.
This immobilization/encapsulation process
reduces leachability of hazardous materials in
conformance with applicable federal, state, and
local regulations (STC, 1988). A description of
the STC immobilization technology which
utilizes calcium-aluminum-silicate compounds
for the treatment of organic as well as inorganic
hazardous wastes, sludges, and soils, and its
attendant applications is presented in the
following section.
STC's Immobilization Technology
The STC immobilization technology is a
solidification/stabilization treatment process that
utilizes a proprietary product (FMS silicate)
developed by STC to selectively adsorb organics
in amounts up to 20 times its weight. When
combined with a cementitious material, the
reagents selectively adsorb organic and inorganic
contaminants and yield a high-strength monolith.
The resulting rock-like materials have reportedly
passed federal and state regulatory threshold
levels for TCLP and CALWET leachate tests,
respectively. Additionally, there have been
demonstrated indications that the resultant
leachability decreases with age.
Two distinct groups of STC proprietary
reagents, utilizing silicate-based formulations,
have been developed. One group of reagents is
used for treating inorganic-contaminated wastes;
another group of reagents has been utilized in
47
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the treatment of organic wastes. The stabiliza-
tion of the organic waste to prevent leaching
occurs as a result of applying the reagent in a
single step that initiates three simultaneous
chemical reactions. The organic compounds in
the waste are sequestered by organically surface-
modified alumino-silicate minerals. When this
compound is mixed with organic waste, it bonds
the organic compounds into the layers of the
organically surf ace-modified alumino-silicate
compound by a partitioning reaction. The
surface-modified layers in the compound can
ultimately adsorb as much as 20 times their own
weight in organic waste, and the adsorbed or-
ganic waste cannot be physically squeezed out of
the layered silicate structure.
Soil stabilization of organic- and inorganic-
contaminated wastes occurs as a result of for-
ming organophilic silicate compounds that react
with the contaminants in the waste and im-
mobilizing them to prevent their leaching. This
results in a very stable compound analogous to
common rock-forming silicate minerals with
excellent physical strength and very low leach-
ability. The process is depicted in a flow dia-
gram in Figure A-l.
Applications of the STC Technology
Organic Contaminants
Hazardous wastes in a soil or sludge medium
containing organic contaminants such as halo-
genated, aromatic, and aliphatic hydrocarbons
are treated through STC's contaminated soil
process. STC claims that the concentration level
of the organic contaminants listed above is not
relevant to the success of the treatment process
since STC's proprietary reagents are adjusted
accordingly. It should be noted that STC re-
agents are not as successful on low-molecular-
weight organic contaminants such as alcohols,
ketones, and glycols.
Inorganic Contaminants
Hazardous wastes in soils or sludges con-
taining inorganic contaminants such as heavy
metals, arsenate, chromate, selenium, fluorides,
and cyanides are treated through STC's con-
taminated soil process, as demonstrated at the
SPT site and shown in the various case studies
described in Appendix C.
Summary
Since 1982 STC has been directly involved in
the successful treatment of organic and inorganic
hazardous wastes including contaminated soils
and sludges. The treatment programs are based
on the utilization of a proprietary product
developed by STC. This product (FMS Silicate)
is an organophilic silicate that selectively adsorbs
organics in amounts up to 20 times the weight of
FMS Silicate. The STC solidification/stabiliza-
tion treatment process has been utilized to render
characteristic hazardous wastes, contaminated
soils, and sludges as nonhazardous. (STC, 1987).
References
STC, 1987. Technology and Services: Cost
Effective Solutions to Your Hazardous Waste
Management Problems.
STC, 1988. Proposal for U.S. EPA, SITE 003,
Organophilic Silicate Processes for
Remediation of Both Soil and Water at
Complex Hazardous Sites.
48
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Figure A-l Contaminated Soil Process Flow Diagram
EXCAVATE
MATERIALS
COARSE
SCREENING
SHREDDING
SHREDDED FINES
HYDRATION
WATER
BATCHING
REAGENTS
CURING AND
TESTING
DISPOSAL
ON-SITE
OFF-SITE
49
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Appendix B
SITE Demonstration Results
-------
Appendix B
Table of Contents
Section Page
Introduction 53
Site Background 53
Site Description 54
Site Contamination Characteristics 54
SITE Demonstration Procedures 57
Review of Treatment Results 61
References 86
List of Tables
Table Pace
B-l Analytical and Measurement Methods 62
B-2 Analytical Results for STC-Treated Wastes 64
B-3 Metal Analyses of Water and Sand Additives 69
B-4 Metal Analyses of Reagent Mixture (Sand Plus Reagents) 69
B-5 Analytical Results for CALWET 72
B-6 Results of TCLP, TCLP-Cage, and TCLP-Distilled Water for Treated Wastes 74
B-7 ANS 16.1 Leachate Analyses for STC-Treated Waste (Batch 3) 74
B-8 Oil and Grease Analysis 75
B-9 Analytical Results for pH, Eh, Loss on Ignition, and Neutralization Potential for
Raw and Treated Waste 76
B-10 pH, Eh, Loss on Ignition and Neutralization Potential for Sand, Water, and STC
Reagent Mixture 76
B-11 Physical Characteristics of Raw Wastes and Sand 78
B-12 Physical Characteristics of STC-Treated Wastes and Reagent Mixture 78
B-13 Wet/Dry Weathering of STC-Treated Wastes 79
B-l4 Freeze/Thaw Weathering of STC-Treated Wastes 79
B-15 Petrographic Analysis of STC-Treated Wastes 81
B-16 Abundance of Mineralogic Phases in X-ray Diffraction Analysis of Raw and
Treated Waste 82
B-17 Long-Term Test Results 83
B-l8 Long-Term (8-month) Chromium Analysis — TCLP-Distilled Water (Batch 5) 86
B-19 Long-Term Physical Tests 86
List of Figures
Figure Page
B-l Regional Location Map - SPT Site, Selma, California 55
B-2 Areas of Contamination at the SPT Site 56
B-3 SPT SITE Demonstration Layout 58
52
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Appendix B
SITE Demonstration Results
Introduction
The overall goal of the Silicate Technology
Corporation (STC) demonstration at the Selma
Pressure Treating (SPT) site was to evaluate the
effectiveness of the STC technology as a long-
term remedial measure at Superfund sites and
RCRA corrective action sites. The SPT site was
selected for the demonstration based on its waste
characteristics, the results of treatability testing,
and site logistical considerations. STC's technol-
ogy is designed for sites with mixed organic and
inorganic contaminants, including polycyclic
aromatic hydrocarbons (PAH) and heavy metals
as reported by CDM at the SPT site (CDM,
1988a and b). The primary objective of this
demonstration was to determine if the STC
immobilization technology could reduce the
potential teachability and mobility of contami-
nants as measured by TWA for organics and the
TCLP for inorganics. In particular, the princi-
pal contaminants for assessing the STC technolo-
gy were pentachlorophenol (PCP) and arsenic.
Additional objectives of this demonstration
include the following:
• Determine if the STC technology
could reduce the leachability of con-
taminants as measured by other
leaching procedures.
• Determine if the STC technology
could reduce leachate concentrations
of PCP and metals below applicable
regulatory limits to allow for legal
disposal as a nonhazardous waste.
• Determine the homogeneity of mix-
ing and structural characteristics of
the STC treated waste.
• Determine the volume and density
increase of the solidified material
due to added reagents.
• Determine if the STC technology
could treat contaminated soils to
produce a monolithic block that
would resist the effects of weather-
ing.
• Determine whether the treated, so-
lidified waste could maintain its
structural properties and stabilization
effectiveness over a 3-year period.
• Develop capital and operating cost
models for the technology that can
be used reliably in the Superfund
and RCRA decision-making process.
This appendix presents the results of the STC
SITE demonstration, in addition to providing
background information about the SPT site in
Selma, California, and the waste characteristics
at this site.
Site Background
The SPT site has been used for chemical
treatment of lumber since 1942. The original
wood-preserving process consisted of dipping
the lumber into a mixture of PCP and oil, and
allowing the excess fluid to drip off as the wood
dried on open storage racks. In 1965, site opera-
tors converted to a pressure-treating process that
consisted of two steps: (1) conditioning the
lumber to reduce moisture content and increase
permeability, and (2) impregnating the wood
with chemical preservatives.
Federal and state agencies have been jointly
involved in regulatory actions at the site since
the 1970s. The California Regional Water Quali-
53
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ty Control Board (CRWQCB) was first to impose
discharge standards, monitor water quality, and
require the owners to submit operational reports.
On January 13, 1981, the following agencies
conducted an Uncontrolled Hazardous Waste Site
Investigation: EPA's Field Investigation Team
(FIT), California Environmental Protection
Agency (CEPA), and CRWQCB. SPT filed for
bankruptcy on April 13, 1981, and the plant
closed its operations in June 1981. On Septem-
ber 4, 1981, CRWQCB issued a Cleanup and
Abatement Order to SPT. SPT indicated it could
not comply with the Cleanup and Abatement
Order; however, an attorney for Selma Leasing
Company (the landowner) indicated to CRWQCB
that Selma Leasing Company would accept
responsibility for the geotechnical investigation
portion of the order. In February 1982 Sawmill
Properties, Inc., acquired the facility, but stipu-
lated that Selma Leasing Company continue to
accept responsibility for the investigations of
contamination caused by past operations. Saw-
mill Properties, Inc., reopened the plant in
Summer 1982, as the Selma Treating Company.
In August 1983, EPA scored the site at 48.83
using the Hazard Ranking System (HRS). Based
on this information, the site was placed on the
Superfund National Priorities List (NPL) in
September 1983. Following a remedial investi-
gation/feasibility study (RI/FS), a Record of
Decision (ROD) was signed on September 24,
1988, and a Pre-Remedial Design Soil Boring
Report was completed in June, 1989 (CDM,
1989).
Site Description
The SPT site is located approximately 15
miles southeast of Fresno, California, adjacent to
the southern city limits of Selma, California
(Figure B-l). The site is situated in the center
of the San Joaquin River Valley, an area that
contains abundant vineyards. The entire SPT
site covers 18 acres; however, the actual wood-
treatment area of this site covers only 3 to 4
acres. While zoned for heavy industrial use, the
site is located in a transition zone between
agricultural, residential, and industrial areas
with approximately 12 residences and businesses
located within 1/4-mile. The CRWQCB has
classified the ground-water resources in the
vicinity of the SPT site as a beneficial use, sole-
source aquifer. This resource provides the
necessary domestic water supply for the sur-
rounding communities and scattered county
residences. Surface-water irrigation systems are
also supplemented by this ground-water re-
source.
Site Contamination Characteristics
From 1942 to 1971, wastes from the treat-
ment plant were disposed of in various ways:
(1) runoff into drainage ditches and a percolation
ditch; (2) drainage into dry wells; (3) spillage on
open ground; (4) placement into an unlined pond
and a sludge pit; and (5) disposal in an adjacent
vineyard (Figure B-2). Known chemical preser-
vatives used at the site include:
• Fluor-chromium-arsenate-phenol
(1966 to 1973)
• Woodtox 140 RTU (1974 only)
• Heavy oil penta solution (1977 only)
• LST concentrate (1970 to 1979)
• Copper-8-quinolinoate (1977 to
1980)
• PCP (1970 to present)
• Chromated-copper-arsenate (CCA)
(1973 to present)
A contaminated ground-water plume ema-
nating from the site has been identified in addi-
tion to pervasive soil contamination beneath the
SPT site. The Pre-Remedial Design Soil Boring
Report (CDM, 1989) for the site indicates that
the primary metal contaminants are arsenic,
chromium, and copper. PCP was also reported
along with associated degradation and impurity
products, including polychlorinated dibenzo-p-
dioxins (PCDD), polychlorinated dibenzofurans
(PCDF), and chlorinated phenols. Hydrocarbon-
related constituents were reported at the site and
may have resulted from the use of diesel fuel as
a carrier for the PCP. The hydrocarbon-related
constituents include volatile organic compounds
such as benzene, toluene, and xylene, and
polycyclic aromatic hydrocarbons (PAH) such as
naphthalene and pyrene. Results from the Pre-
Remedial Design Soil Boring Report (CDM,
1989) and Final Remedial Investigation Report
(CDM, 1988a) confirm that the highest levels of
contamination occur in the first 5 feet of the soil
material.
54
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Figure B-1. Regional Location Map - SPT Site, Selma, California
( I We" ' r
Selma Treating
Company \
*0. J°S~~» ' xJL-V.
55
-------
Figure B-2. Areas of Contamination at the SPT Site
I
\
LU
z
LU
VINEYARD
Waste Sludge Pit
C
Un lined Waste Disposal Pond
A SITE DRAINAGE DISCHARGE
AREAS
B DRAINAGE DITCH
C PERCOLATION DITCH
D DRY WELLS
E AREAS WHERE SPILLS, LEAKS
& DRIPPINGS HAVE OCCURRED
F WASTE DISPOSAL SITES
G PIPELINE FOR OFF-SITE
DISCHARGE OF WASTE
FEET
56
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SITE Demonstration Procedures
The SITE demonstration was divided into
three phases: (1) site preparation; (2) technology
demonstration; and (3) site decontamination,
demobilization, and waste disposal. These
activities and a review of technology and equip-
ment performance during these phases are
described below.
Site Preparation
Site preparation began 1 week prior to the
treatment technology demonstration. EPA and
its contractors established a waste treatment
decontamination area, staging and storage areas,
a decontamination zone, and a public viewing
area as depicted in Figure B-3. The personnel
decontamination pad was 6 feet wide, 10 feet
long, and 2 feet deep on one end. A layer of
20-mil high-density polyethylene (HOPE)
attached to railroad ties was used to line the
decontamination pad. A pump was placed in the
decontamination pad to provide for the collec-
tion of all rinsate resulting from equipment
decontamination. Decontamination of construc-
tion equipment was conducted on 20-mil HDPE
in the waste excavation pit.
On-Site Logistics
To successfully meet the demonstration
objectives, the EPA SITE team and STC person-
nel used the following on-site provisions:
• A 50- by 100-foot compacted soil
area for the STC process equipment
and temporary accumulation of
waste and treatment reagents. The
process equipment area was con-
structed with a plastic liner and
berm.
• A 45- by 6-foot gravel and com-
pacted soil area for the office and
laboratory trailer. An area appropri-
ate for parking and equipment stag-
ing was also provided.
• A 15- by 50-foot area lined with 20-
mil HDPE liner to place and store
the solidified waste. The treated
waste was discharged into cardboard
concrete forms mounted on pallets,
and placed in the storage area. The
storage area was graded in such a
way that a low point in the liner
existed for collection of any
rainwater runoff from the solidi-
fied waste.
• A dumpster for containment and
disposal of all nonhazardous waste.
• Diesel electric generator to supply
480-volt, 3-phase, 500-amp service
for STC process equipment. In addi-
tion, standard electric power was
provided by a portable generator for
the support trailer, equipment, and
miscellaneous needs.
• Process and wash water for the treat-
ment unit and decontamination. This
water was obtained from the facili-
ty's potable water. Approximately
220 gallons of water were required
per treated batch.
• A scale for weighing reagents and
raw wastes.
• A heavy equipment decontamination
area bermed and lined with 20-mil
plastic for cleaning large equipment.
This area was also provided with a
pump for the collection of wash
water.
• A personnel decontamination station
adjacent to the equipment decontam-
ination area. The station was sup-
plied with appropriate basins, brush-
es, water, and soap. This area also
included several tables to function as
an equipment drop, a first-aid sta-
tion, and emergency eye-wash facili-
ties.
• A 3,000-gallon Baker wastewater
tank used to contain decontamination
water.
• A gasoline-powered, high-pressure
cleaner to clean the STC process
equipment and other heavy equip-
ment.
57
-------
o
(8
«
••o82£
^ m S <
co co
I
i
I
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5
o
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e
58
-------
• Three 55-gallon drums to contain
contaminated clothing, supplies, and
other materials that could not be
disposed of in the dumpster. These
drums were disposed of at appropri-
ate off site facilities.
• A 45-foot office and sampling trailer
for EPA, contractor, and STC per-
sonnel.
• A portable telephone for ordering
supplies, scheduling deliveries, and
emergency communications.
• Sanitary facilities for personnel in-
volved with the demonstration.
• A public viewing area for the dem-
onstration.
• A locked chain-linked fence con-
structed around the work area upon
completion of the demonstration.
Entry to the SPT property was re-
stricted during the demonstration
between 5:00 p.m. and 8:00 a.m.
Technology Demonstration
This section discusses waste collection proce-
dures as well as equipment startup and test run
procedures. In addition, operational and equip-
ment problems along with health and safety
considerations are addressed.
Collection of Waste Material for Treatment
A backhoe/front-end loader was used to
collect contaminated waste material from the
unlined waste disposal pond. To ensure that the
waste with the highest concentration of contami-
nants was tested, the first 3 feet of soil material
from the disposal pond were used for the dem-
onstration. Therefore, it was necessary to exca-
vate approximately a 300-square-foot area to a
depth of 3 feet to provide the total amount of
contaminated soil needed for the demonstration.
The excavation was lined with a layer of 20-mil
HDPE and backfilled with 1 foot of sand over-
laid by 1 foot of crushed stone (1 -inch diameter)
and clean soil at the conclusion of the demon-
stration.
Contaminated soils from the unlined waste
disposal pond were transported directly to the
processing area, where temporary storage piles
covered by 10-mil HDPE were set up as neces-
sary prior to batch processing. Each batch was
thoroughly mixed in a 5-cubic-yard high-inten-
sity batch mixer prior to the addition of STC
reagents.
Equipment Startup and Test Runs
Upon completion of the equipment setup,
STC conducted a startup and test run to ensure
that the equipment was operating properly and
that all SITE team members understood the
sampling procedures. During this procedure, a
small batch of treatment reagents (695 Ibs) with
clean silica sand (1,972 Ibs) instead of waste
material was processed. This initial "reagent
mixture" constituted a treatment process blank.
Treatment startup began with the transport
of approximately 5,000 Ibs of raw waste material
to the mixer. The contaminated soil was blended
in the mixer until STC confirmed the waste was
adequately homogenized. Pretreatment grab
samples were taken directly from the mixer
discharge at three separate intervals and placed
into sample containers prior to the addition of
treatment reagents. Mixing continued for up to
1 hour following the addition of treatment
reagents and water. The treated material was
then discharged into three 1-cubic-yard card-
board forms. Samples were collected from the
forms immediately after the treated waste was
discharged from the mixer. For each batch run,
complete records were maintained of pertinent
operating parameters including weight of the soil
waste, STC reagents, and water added; mixer
power; and mixing time (see Table 3-1 of the
Application Analysis Report).
Operational Problems
A few operational problems were encoun-
tered during the STC SITE demonstration. These
operational problems included (1) incomplete
mixing of certain wastes (especially during Batch
2) and (2) excessive dust generation from the
movement of equipment and site personnel.
Both of these operational problems, and respons-
es to these problems, are discussed in detail
below.
59
-------
Certain contaminated soils (the PCP-encrust-
ed "hardpan") treated during the demonstration
were not well mixed after treatment; the treated
waste contained large (up to 2-inch) inclusions
of untreated waste. This problem resulted in the
exclusion of Batch 2 from analytical evaluation.
The problem was solved in subsequent batches
by forcing the raw waste through a series of
screens prior to treatment, reducing the raw
waste aggregate size to approximately 0.04 to
0.08 inch (1-2 mm) diameter. This pretreatment
allowed for adequate mixing to occur; the subse-
quent batches (i.e., Batches 3 through 5) ap-
peared to be homogeneous mixtures.
The generation of large amounts of contami-
nated dust from the movement of equipment,
supplies, and site personnel caused fouling of the
intake to the photoionization device that was
used for air monitoring. The dust problem was
remedied through the application of water to the
site from a water truck. An additional opera-
tional problem was the dust cloud created upon
initially mixing the dry reagents in the mixer. A
portion of the necessary water was added to the
homogenized waste before the addition of dry
reagents; however, the short amount of time it
took to thoroughly wet the dry reagents still
resulted in the generation of a dust cloud.
Consequently, a tarp was secured over the top of
the mixer after adding dry reagents. Although
no downwind residents or receptors were affect-
ed by the small dust cloud of finely divided dry
reagents during the demonstration, slurrying the
reagents prior to addition may be desirable for
future uses of the technology.
Health and Safety Considerations
The overall hazard rating for the SPT site
was moderate as indicated by preliminary analy-
ses, which reported high concentrations of
semivolatile organic compounds and toxic heavy
metals. Several compounds were suspected
carcinogens. Potential routes of exposure during
the demonstration were inhalation, ingestion,
and skin and eye contact during sample trans-
port, treatment, and collection.
All personnel working at the SPT site had, at
a minimum, 40 hours of health and safety train-
ing and were under routine medical surveillance.
Personnel were required to wear protective
equipment appropriate for the activity being
performed. A modified Level D protection was
recommended; however, personnel working in
direct contact with contaminated soils donned
Level C protective equipment including a full-
face respirator with GMA-H cartridges, Tyvek
coveralls, steel-toed leather work boots and
rubber booties, hard hat, latex inner gloves, and
nitrile outer gloves.
Decontamination, Demobilization, and Waste
Disposal
Prior to waste collection activities, all STC
equipment that would come in contact with raw
waste materials was decontaminated. In addi-
tion, all process equipment was decontaminated
between batch runs and at the conclusion of the
demonstration. A portable high-pressure cleaner
was used to decontaminate the equipment. Water
and wastes generated from the cleaning of
equipment were pumped to a 3,000-gallon Baker
wastewater tank and stored on site for
subsequent disposal. Personnel decontamination
wash water and wastes were collected from wash
basins and also placed in this tank for off-site
disposal. All sampling equipment was cleaned
with a nonphosphate detergent and triple rinsed
with distilled water before reuse. The wash
water containing soap was drummed and stored
on site for disposal.
Once all test runs were completed and
equipment decontaminated, all test equipment
was demobilized and removed from the SPT site.
Decontamination and demobilization took
approximately 2 weeks. The demonstration
wastes included 1,000 gallons of water and
wastes from decontamination, three 55-gallon
drums of contaminated clothing and disposable
sampling supplies, and a 30-cubic-yard
dumpster containing miscellaneous nonhazardous
trash. The decontamination wastes, drums, and
dumpster wastes were disposed of by EPA and
its contractors at appropriate facilities.
The 1 -cubic-yard cardboard form containing
treated clean sand and 15 similar forms filled
with treated wastes were placed on wooden
pallets in the western section of the
demonstration site. After 28 days, the cardboard
forms were removed and disposed. The exposed
monoliths of treated waste will be inspected
periodically for 3 years. After the 3-year
monitoring period ends, EPA will dispose of
these wastes according to the cleanup criteria
selected for the SPT site and all applicable or
60
-------
relevant and appropriate requirements.
Review of Treatment Results
This section summarizes the results of analy-
ses for critical analytes as well as noncritical
parameters for the STC solidification/stabiliza-
tion demonstration as delineated in the STC
SITE Program Demonstration Quality Assurance
Project Plan (QAPjP). This section also evalu-
ates the technology's effectiveness in reducing
the mobility and leachability of selected toxic
contaminants.
Testing Approach
Preliminary testing at the SPT site indicated
that the contaminated areas contained essentially
similar contaminants but in varying concentra-
tions (CDM, 1988a and b, and 1989). The
highest levels of contaminants were reported
from the unlined dry waste disposal pond.
Contaminated soils from this area were treated
during the demonstration to provide the most
severe conditions for determining treatment
effectiveness.
The contaminants of regulatory concern at
the SPT site were arsenic and PCP which were
targeted for treatment during the demonstration.
Other non-target contaminants were chromium,
copper, nickel, and lead, as well as other semi-
volatile organic compounds such as phenan-
threne, tetrachlorophenol, phenol, and naphtha-
lene. The corresponding critical measurements
for the demonstration were TCLP for arsenic
(and other inorganic analytes) and TWA for PCP
(and other organic analytes). Noncritical mea-
surements included TCLP for organic analytes,
and TCLP-Distilled Water and CALWET leach
procedures for both organic and inorganic
analytes. Additional noncritical measurements
for the demonstration included the TCLP-Cage
and a modified American Nuclear Society (ANS)
16.1 leach test, analysis for PCDDs and PCDFs,
engineering and geotechnical tests, and petro-
graphic examination. In addition, chemical
characterization of the raw and treated waste
included pH, Eh, loss on ignition, and neutral-
ization potential analyses. Acid neutralization
capacity tests originally planned for the raw
wastes to determine the buffering capacity could
not be completed due to the slightly acidic
nature of the raw waste samples. Instead, neu-
tralization potential measurements were con-
ducted on both the raw waste and treated waste
samples for comparison purposes.
For critical measurements, six or more field
replicate samples of raw and treated waste were
collected, depending on data variability as deter-
mined in the initial treatability tests from the
SPT site. Field replicate samples were analyzed
for arsenic, chromium, copper, nickel, lead, and
semivolatile organic compounds including PCP.
In addition, field replicate geotechnical/engi-
neering samples were collected for unconfined
compressive strength, permeability, and petro-
graphic examination, but not for particle size,
water content, bulk density, wet/dry, or freeze/
thaw testing.
EPA-approved sampling, analytical testing,
and quality assurance and quality control
(QA/QC) procedures were followed to obtain
data of known quality. Details on QA/QC
procedures are presented in Volume III of the
demonstration plan (U.S. EPA, 1990). A quality
assurance review of the demonstration data was
performed by Engineering-Science, Inc. Details
of this review can be found in the report "Draft
Data Summary for the STC SITE Demonstra-
tion," ES, November, 1991. In general, the
usability of the data generated by Engineering-
Science, Inc. Berkeley Laboratory (ESBL) to
meet the objectives of the demonstration was not
affected by the QA outliers found during valida-
tion of the data. Table B-1 summarizes analyti-
cal and measurement methods.
Summary of Results for Critical Analytes
Analytical results for arsenic, chromium,
copper, and pentachlorophenol (PCP) in waste
material treated by STC using the TCLP, TCLP-
Distilled Water, and TWA methods of analysis
are presented in Table B-2. Nickel, lead, and
semivolatile organic compounds other than PCP
were consistently undetected in both raw and
treated waste analyses, and therefore are not
included in the results of this report. For each
analyte the results are reported as average values
for six or more samples of raw and treated waste
and include standard deviation values. In addi-
tion, the results include calculated percent
reductions accounting for dilution effects of
added reagents by incorporating the additives
ratio for each batch tested. This ratio is the
weight of additives, including water of
hydration, divided by the weight of raw wastes.
61
-------
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CO
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s
fied
Pb,TI,As,Se
> 0
'io i
* 6
PCDDs a
DFs
62
-------
1
III
f 1
1 .
Ill
&-Monto
Long-Term
Digestates
i
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ofl
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II
s<
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-
EPA 9045
•
•
I
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•
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-
Modified
EPA 9045
*
•
< a
.
•
•
jf
1 Neutralization
Potential
X
-
-
•
Is
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•
Modified
EPA 413.2
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•
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TMSWC4
|| Content
I
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TMSWC-2
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•
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TMSWC-13
Permeability
•
*
•
< Q
1 Unconfined
Compressive
Strength
•
•
TMSWC-12
1 Wet/Dry
Weathering
•
•
TMSWC-11
1 Freeze/Thaw
Weathering
•
•
Modified
ASTM
C457/C856
Petrographic
63
-------
Table B-2. Analytical Results for STC-Treated Wastes
Constituent
Arsenic - TCLP
Arsenic - TCLP
Distilled Water
Arsenic - TWA
Arsenate (V)d
Arsenite (III)"
Batch
1
3
4
5
Sand
RM
1
3
4
5
RM
1
3
4
5
Sand
RM
3
4
5
3
4
5
Concentrations (ppm)
Raw Waste"
1.82 ±0.47
1.06 ±0.23
2.40 ± 0.60
3.33 ± 0.33
<0.01
—
0.80 ± 0.21
0.73 ± 0.06
1.25 ±0.12
1.07 ±0.09
—
470 ± 220
270 ± 60
1,700 ± 200
2,180 ± 320
<2
—
60.5
19.5
260
<2.0
205
<2.0
Treated Waste*
0.086 ± 0.055
0.101 ± 0.030
0.875 + 0.153
0.548 ± 0.095
—
<0.01
<0.01
<0.01
0.011 ±0.001
0.012 ± 0.001
<0.01
310 ± 40
198 ± 70
1,000 ± 120
1,550 ±570
—
2.5
<2.0
21
<2.0
<2.0
7.5
<2.0
Percent Reduction*'
92 (81.5-97.6)
83 (72.2 - 90.3)
35 (-1.43 - 57.3)
71 (62.6 - 78.4)
—
—
>98 (97.0 - 98.3)
>98 (97.3 - 97.8)
98 (98.1 - 98.7)
98 (97.7 - 98.3)
—
—
—
—
—
—
—
—
—
—
—
—
—
64
-------
Table B-2. Analytical Results for STC-Treated Wastes (Continued)
Constituent
Chromium -
TCLP
Chromium -
TCLP Distilled
Water
Chromium -
TWA
Batch
1
3
4
5
Sand
RM
1
3
4
5
RM
1
3
4
5
Sand
RM
Concentrations (ppm)
Raw Waste'
0.13 ± 0.09
<0.05
0.10 ±0.06
0.27 ± 0.05
<0.05
—
0.1 9 ±0.07
0.17 + 0.05
0.07 ± 0.01
0.11 ±0.04
—
410 ± 80
340 ± 90
1,750± 80
2,120 ±210
<10
—
Treated Waste*
0.245 ± 0.005
0.187 ±0.012
0.278 ± 0.010
0.320 ± 0.033
—
<0.07
<0.05
<0.05
0.056 ± 0.006
0.079 ± 0.003
<0.05
340 ± 10
270 ± 50
950 ± 60
1,270 ±160
—
12
Percent Reduction*-1
-230 (-1,000 -(-92))
NC
-390 (-1,179- (-197))
-110 (-181 - (-56))
—
—
>54 (27 - 66)
>48 (27 - 66)
-42 (-84 -(-11))
-25 (-105 - 12)
—
—
—
—
—
—
—
65
-------
Table B-2. Analytical Results for STC-Treated Wastes (Continued)
Constituent
Copper - TCLP
Copper - TCLP
Distilled Water
Copper - TWA
Batch
1
3
4
5
Sand
RM
1
3
4
5
RM
1
3
4
5
Sand
RM
Concentrations (ppm)
Raw Waste*
3.42 ± 1.16
1.3810.15
6.53 ± 1.11
9.43 ± 1.40
<0.03
—
0.45 ±0.16
0.37 ± 0.08
0.99 ± 0.06
0.56 ±0.10
—
370 ± 47
330+ 48
1,170 ± 52
1,270 ± 52
<6
—
Treated Waste*
0.090 ± 0.005
0.075 ± 0.007
0.103 ± 0.005
0.062 ±0.012
—
<0.03
0.031 ±0.001
<0.030
0.054 ± 0.002
0.032 ± 0.001
<0.03
280 + 10
210+ 16
630 ± 34
780 ± 97
—
<6
Percent Reduction*-*
95 (92.6 - 96.7)
90 (88.1 - 92.3)
97 (96.5 - 97.7)
99 (98.4 - 99.2)
—
—
88 (81.1-91.5)
86 (81.4 - 88.3)
90 (89.3 - 91.1)
90 (87.4 - 92.0)
—
—
—
—
—
—
—
66
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Table B-2. Analytical Results for STC-Treated Wastes (Continued)
Constituent
PCP - TCLP
PCP - TCLP
Distilled Water
PCP - TWAe
PCP - TCLP
pH 12d-f
Batch
1
3
4
5
1
3
4
5
1
3
4
5
1
3
4
5
Concentrations (ppm)
Raw Waste"
1.50 ± 0.13
2.27 ± 0.33
1.75 ± 0.57
2.28 ± 1.40
34.7 ± 16.4
40.0 ± 18.4
40.5 ± 10.5
79.7 ± 17.9
2,350 ± 660
1,980 ± 270
7,700 ±1,080
8,320 ±1,440
110
88
320
320
Treated Waste*
3.42 ± 1.50
<0.250
5.52 ± 0.32
0.90 ± 1.25
3.98 ± 1.78
0.58 ± 0.08
3.87 ± 0.46
3.05 ± 0.85
120 ± 40
90 ± 30
120 ± 40
220 ±150
6.2
1.9
13
17
Percent Reduction*-'
-302
>81
-460
31
80
97
83
93
91
92
97
95
(-532 -(-107))
(77 - 99)
(-779 - (-298))
(-326- 117)
(44.7 - 92.4)
(94.6 - 98.5)
(74.4 - 88.1)
(89.0 - 96.1)
(83.3 - 95.3)
(87.6 - 95.3)
(95.7 - 98.4)
(90.6 - 98.7)
90
96
93
91
Arsenic and PCP were target analytes for treatment for the technology demonstration; chromium and copper were not.
RM - Reagent mixture
NC = Not calculable
a = Results for individual batches reported as the mean and standard deviation of six or more samples.
b = Percent Reduction = fl - (l * Additives Ratio) * Concentration of netted Wast*] x 100.
[ . Concentration of Raw Waste j
The low end of the percent reduction range was calculated by subtracting the standard deviation from the raw
waste mean and adding the standard deviation to the treated waste mean to produce a worst-case value. The
high end of the percent reduction range was calculated by adding the standard deviation to the raw waste mean
and subtracting the standard deviation from the treated waste mean to produce a best-case value.
c = The additives ratio is the weight of additives including water ofhydration, divided by the weight of raw wastes.
Values are 0.761, 0.764, 0.776, and 0.746 for Batches 1, 3, 4, and 5, respectively.
d = Results reported as mean of duplicate analyses.
e = Estimated average concentrations using twice the method detection limit for non-detected analyses.
f - 0.1 M borate buffer solution used in leaching.
67
-------
Thus, percent reduction was calculated using the following formula:
Percent Reduction = [l - (1 + Additives Ratio) X Concentration of Treated Waste
Concentration of Raw Waste
x 100.
When a constituent was not detected in the
treated waste, the reporting limit for the treated
waste constituent was used to calculate a mini-
mum value for the percent reduction (indicated
by ">").
Reporting limits were determined by multi-
plying the method detection limit by the dilution
factor for each specific analysis. The reporting
limits were not considered useful for TWA of
post-treatment PCP due to very large dilution
factors required to reach the quantitation range
for PCP analysis, thus forcing the reporting
limits for PCP to unreasonably high levels. The
STC TER reports the results of additional analy-
ses of raw and treated waste samples that were
analyzed for PCP by TWA using non-standard
dilution steps to obtain lower reporting limits.
These results justify the use of estimated con-
centrations in calculating percent reductions and
generally show even greater percent reductions
than using the estimated values. Treated waste
concentrations for total waste analysis of PCP,
therefore, consist of estimates using twice the
method detection limit for non-detected analy-
ses. Such an estimate is more reasonable, yet
still conservative. If a constituent was not
detected in the raw waste, the percent reduction
was not calculable. As a result of the dilution
associated with treatment, negative percent
reduction values may be expected even if the
concentrations show a decrease in concentration
from the raw to the treated waste.
In general, the percent recovery for semi-
volatile surrogates, and acid surrogates in partic-
ular, were consistently extremely low. In many
of the samples containing the reagent mix, no
acid surrogates were recovered. These results
suggest that a significant portion of the spiked
compounds remained adsorbed to the reagent
mixture during the analysis. These results also
indicate that the reagent mixture would have the
same effect on target compounds similar to the
surrogates. This trend supports the effectiveness
of the reagent mixture on phenolic compounds
since all three acid surrogate compounds were
phenols.
Inorganics
Although arsenic was the main metal con-
taminant of regulatory concern at the SPT site,
chromium, copper, nickel, and lead were also
analyzed in replicate samples using the various
leach tests and TWA analysis. Nickel and lead
were consistently undetected in both raw and
treated waste analyses and therefore are not
included in the results of this report. In addi-
tion, routine analyses were performed for the 23
standard Hazardous Substance List (HSL) metals,
plus molybdenum (which is included in the
CALWET testing). These analyses typically did
not identify additional anomalously high concen-
trations of metals other than elements commonly
found in soils, such as iron and aluminum.
Thus, the metals selected for this report are
limited to arsenic, chromium, and copper. TWA
results for the selected metals are included in
this report despite the fact that concentrations of
total metals are not expected to be reduced by
the STC process; therefore, percent reductions
have not been included. Metal analyses of the
water and silica sand additives for TWA and
TCLP are presented in Table B-3. In addition,
Table B-4 presents metal analyses of STC's
reagent mixture with clean sand for the various
leach tests and TWA.
Arsenic
In general, leach results indicated that arsen-
ic was well stabilized by the STC treatment
under neutral conditions. Acidic leaching, as
under TCLP conditions, resulted in greater
arsenic mobility for both the raw and treated
waste. This observed increased arsenic mobility
is, at least in part, due to the amphoteric nature
of arsenic, whereby its solubility increases as the
pH of the leachate either decreases or increases
away from neutral conditions.
Using the TCLP, results for arsenic varied
among the four batches evaluated, with percent
reductions ranging from 35 to 92 percent. Batch
4 depicts an anomalously low percent reduction
of only 35 percent. This poorer-than-expected
performance may be attributed to the inordi-
nately long raw-waste-mixing time for this
batch (4.5 hours). Supplemental ion
68
-------
Table B-3. Metal Analyses of Water and Sand Additives
Constituent
Aluminum
Arsenic
Calcium
Chromium
Copper
Iron
Magnesium
Manganese
Potassium
Sodium
Zinc
Water - TWA' (ppm)
<0.2
<0.01
20
<0.05
<0.03
0.05
4.1
<0.02
2.15
17
0.037
Sand - TWA (ppm)
780
<2
310
<10
<6
1,200
<200
9.3
<200
<200
<4
Sand - TCLP (ppm)
0.30
<0.01
11
<0.05
<0.03
<0.1
<1
0.072
1.1
1,300
0.053
a = Results reported as mean of duplicate samples.
Table B-4. Metal Analyses of Reagent Mixture (Sand Plus Reagents)
Constituent
Aluminum
Arsenic
Barium
Calcium
Chromium
Copper
Iron
Magnesium
Manganese
Potassium
Selenium
Sodium
Zinc
TWA
(ppm)
4,300
2.5
27
61,000
12
<6
3,100
930
27
1,400
<1
1,100
8.1
TCLP
(ppm)
<0.2
<0.01
0.21
1,900
0.07
<0.03
<0.05
5.5
<0.02
19
—
16
<0.02
TCLP
Distilled Water
(ppm)
0.56
<0.01
0.40
660
<0.05
<0.03
<0.05
<1
<0.02
19
<0.005
14
<0.02
TCLP-Cage
(PPm)
<0.2
<0.07
0.21
2,000
0.053
<0.03
<0.05
11
<0.02
15
0.006
23
<0.02
CALWET
(ppm)
15
<0.1
<1
1,200
<0.5
<0.3
24
<10
0.32
51
<0.05
8,600
0.39
69
-------
chromatography analyses of arsenic for selected
TWA extracts from Batches 3, 4, and 5 indicate
that the raw waste from Batch 4 contained
higher quantities of the arsenic ion-species
arsenite (205 ppm) and lower values of arsenate
(20 ppm) relative to Batches 3 and 5 that had
high arsenate (61 and 260 ppm, respectively) and
low arsenite values (<2 ppm in both batches). It
is likely that most of the Batch 4 arsenic was
reduced from arsenate (V) to arsenite (III)
during the long raw-waste-mixing process,
thereby rendering the treated contaminants more
mobile and easily leached under acidic TCLP
conditions. Alternatively, the STC process was
not effective in converting the arsenite to
arsenate or a species which could be chemically
immobilized; minor amounts of both arsenite and
arsenate were detected in the Batch 4 treated
waste.
Excluding results from Batch 4, percent
reductions for arsenic under TCLP conditions
range from 71 to 92 percent. Values for arsenic
as analyzed by the TCLP-Distilled Water method
show the highest percent reductions of 98
percent for all four batches. This leach method
was not affected by the arsenic speciation
differences observed in Batch 4. Concentrations
of arsenic were, however, lower than TCLP
regulatory levels in each of the four batches for
both the raw and treated wastes.
Chromium
Due to low leachable concentrations in the
raw waste, chromium was not a contaminant
targeted for treatment during the demonstration.
That is, no special measures were taken to treat
chromium. Therefore, the STC treatment pro-
cess was not as consistently effective in immobi-
lizing chromium as it was for arsenic. Chromi-
um was generally rendered immobile by STC's
treatment process under neutral leaching condi-
tions. However, under acidic leaching condi-
tions, chromium was more mobile and leachable
in the treated waste; chromium concentrations
for the treated wastes were significantly higher
than for the raw wastes in all but one treatment
batch. The results indicate that if chromium is
targeted for treatment, the combination of
treatment additives should be adjusted to make
the treatment more effective.
TCLP tests for chromium showed large
negative values for percent reduction ranging
from -107 to -394 percent. Leachate concentra-
tions of chromium from the raw waste of Batch
3 were below detection limits and therefore per-
cent reductions were not calculable. Values from
analysis using the TCLP-Distilled Water method
showed more variability with percent reductions
ranging from -42 percent to greater than 54
percent. It should be noted, though, that all of
the TCLP-Distilled Water values for the treated
waste were at or near the detection limit as were
the concentrations of chromium in the raw waste
for the batches resulting in negative percent
reduction values.
TWA analyses of the STC reagent mixture
indicated an addition of small amounts of chro-
mium (12 ppm) as a result of the STC treatment
process. In addition, TCLP leachate from the
reagent mixture indicated that 22 to 37 percent
of the concentration of leachable chromium in
the treated waste was a result of the treatment
process.
The raw waste showed no differences in
leachability between acidic and neutral TCLP
conditions. Furthermore, despite the large
batch-to-batch range of total chromium concen-
trations in the raw waste, the leachate concen-
trations of the raw waste under both acidic and
neutral TCLP conditions are essentially the same.
(That is, the distribution of leachate concentra-
tions overlap.) However, leachable chromium
concentrations in the raw waste are very low —
well below regulatory levels for the TCLP.
Treated waste concentrations of chromium were
also below these regulatory levels.
Copper
Copper was not a targeted contaminant for
treatment during this demonstration. However,
treated waste leachate concentrations indicated
that copper was effectively stabilized under both
acidic and neutral TCLP conditions. Copper in
the raw waste was considerably less mobile under
neutral conditions than under acidic leaching
conditions.
Both the TCLP and the TCLP-Distilled
Water methods of analysis showed consistently
high percent reductions of copper. The TCLP
percent reduction values ranged from 90 to 99
percent while the TCLP-Distilled Water method
indicated only slightly less effective treatment
with percent reduction values ranging from 86 to
70
-------
90 percent (although the pretreatment concen-
trations of copper were much lower under
neutral conditions). Initial copper concentra-
tions in the raw wastes for both the TCLP and
TCLP-Distilled Water tests were low (<10 ppm
and <1 ppm, respectively); however, no TCLP
regulatory threshold concentration has been
established for copper.
Organics
Pentachlorophenol (PCP) was the main
organic contaminant of concern at the SPT site.
Based on the information from the treatability
study at the site, however, replicate samples
were also analyzed for other constituents includ-
ing semivolatile organics such as tetrachloro-
phenol (TCP), phenanthrene, naphthalene, and
phenol. These constituents were ultimately
detected in negligible concentrations, and there-
fore were not included in this report.
Pentachlorophenol (PCP)
PCP concentrations for the TWA extracts
show percent reductions as a result of the STC
stabilization process ranging from 91 to 97
percent. Results of the TCLP at varying pH
levels (waste sample size, leachate volume and
leaching time the same as for the standard
TCLP) indicated that the teachability of PCP in
the raw waste was a function of pH. Raw waste
leachates showed greater PCP mobility under
neutral TCLP-Distilled Water leaching condi-
tions than under the standard acidic TCLP
conditions. Although TCLP analysis at pH 12 is
not a standardized leach test, this method (using
a 0.1 M borate buffer solution) indicated better
results for PCP than either the standard TCLP or
neutral TCLP-Distilled Water leach tests. Per-
cent reductions for PCP by TCLP analysis
conducted at pH 12 ranged from 90 to 96
percent.
The treated waste showed similar leaching
characteristics for both acidic and neutral condi-
tions. Even the TCLP at pH 12 leachate concen-
trations of PCP for Batch 1 and 3 were compara-
ble to neutral and acidic leach conditions. As a
result of the lower leachate concentrations from
the raw wastes, the percent reductions for PCP
range from -460 to 81 percent for the TCLP
(two of the four batches showed increases in
PCP concentrations of the treated wastes), and
80 to 97 percent based on the neutral TCLP-
Distilled Water test method. All raw and treated
waste concentrations were, however, below
TCLP federal regulatory threshold levels of 100
ppm for PCP.
Summary of Other Measurements
Noncritical testing parameters, as outlined in
the STC Demonstration Plan and the QAPjP,
include CALWET, TCLP-Cage, and modified
ANS 16.1 leach tests on stabilized waste samples.
In addition, results for chemical analysis for oil
and grease are included in this section. Each of
these analyses was performed on both raw and
treated wastes. Soil chemical characterization
parameters including pH, Eh, loss on ignition,
and neutralization potential for both raw and
treated wastes, and the solidified reagent mixture
are also briefly discussed. Soil physical parame-
ters and geotechnical analyses include mean
particle size, moisture content, bulk density,
unconfined compressive strength, permeability,
wet/dry and freeze/thaw weathering. Finally,
petrographic examination and X-ray analyses are
provided for generalized qualitative descriptions
of raw and treated waste material. More detailed
information is contained in the STC TER.
CALWET
The CALWET consists of an extraction
similar to that of the TCLP extraction, except
that the CALWET uses a citric acid solution for
leaching solid material over a 48-hour period, at
a liquid-to-solid ratio of 10 to 1. Following the
leaching period, separation of the extracts is
achieved by filtration through a 0.45 urn mem-
brane filter, centrifuging prior to filtration if
necessary. As a result of the greater acid
strength, longer leaching time, and greater
buffering capacity, the CALWET is a more
aggressive leach procedure than the TCLP.
Analytical results for the CALWET are presented
in Table B-5.
Raw waste leachate concentrations of PCP
and arsenic were above the Solubility Threshold
Limit Concentrations (STLC) for the CALWET,
a criteria used by the state of California
(see Table 3-6). Chromium concentrations were
well below the total chromium STLC of 560
ppm, and hexavalent chromium was not
specifically analyzed. Copper showed mixed
results with the raw waste leachate from Batch 3
below the STLC of 25 ppm and Batches 1, 4, and
71
-------
Table B-5. Analytical Results for CALWET
Constituent
Arsenic
Chromium
Copper
PCP
Batch
1
3
4
5
1
3
4
5
1
3
4
5
I
3
4
5
Concentrations (ppm)
Raw Waste*
12.7 ± 1.53
8.8 ± 0.57
28.7 ± 0.58
28.0 ± 1.73
2.97 ± 0.12
2.07 ± 0.15
7.10 ± 0.56
6.90 ± 0.30
27.7 ± 0.58
17.7 ± 0.58
57.7 ± 3.51
61.3 ± 4.73
2.30 ± 0.56
2.60 ± 0.44
3.20 ± 0.10
2.87 ± 0.15
Treated Waste*
4.57 ± 1.07
4.55 ± 1.39
23.3 ± 1.63
20.0 ± 3.41
5.15 ± 0.96
3.80 ± 0.36
19.0 ± 1.10
18.0 ± 1.10
12.3 ± 1.63
8.8 ± 0.45
31.8 ± 1.1
33.0 ± 1.10
12.3 ± 2.08
3.5 ± 1.16
28.7 ± 4.62
31.7 ± 2.89
Percent Reduction **
36.6 (11.1 - 56.7)
8.5 (-27.8 - 40.3)
-44.2 (-57.6 - (-31.4))
-24.7 (-55.6 - 2.57)
-205 (-277 - (-139))
-224 (-282 - (-173))
-375 (-446 - (-315))
-355 (-405 - (-310))
21.8 (9.55 - 33.6)
12.0 (4.38 - 19.1)
2.12 (-7.43 - 10.6)
6.01 (-5.25 - 15.7)
-842 (-1,356 -(-530))
-135 (-277 - (-35))
-1,493 (-1,809 -(-1,196))
-1,829 (-2,123 -(-1,564))
Arsenic and PCP were target analytes for treatment for the technology demonstration; chromium and copper were not.
a = Results reported as the mean and standard deviation of three or more samples.
b = Percent Reduction = [l - (1 * Additives *o«u>) * Concentration of Treattd Wasted x 100
[ Concentration of Raw Waste \
The low end of the percent reduction range was calculated by subtracting the standard deviation from the raw waste mean and
adding the standard deviation to the treated waste mean to produce a worst-case value. The high end of the percent reduction
range was calculated by adding the standard deviation to the raw waste mean and subtracting the standard deviation from the
treated waste mean to produce a best-case value.
c = The additives ratio is the weight of additives, including water of hydration, divided by the weight of raw wastes. Values are
0.761, 0.764, 0.776, and 0.746 for Batches 1, 3, 4, and 5, respectively.
72
-------
5 above this limit.
STC-treated wastes were not effectively
stabilized based on results from the CALWET
procedure. PCP concentrations in the treated
waste leachates were greater than those for the
raw waste leachates, thus resulting in very large
negative percent reductions ranging from -135
to -1,829 percent. Arsenic values showed mixed
results, with percent reductions ranging from
-44 to 37 percent. Although all batches showed
reductions in arsenic leachate concentrations,
only Batches 1 and 3 resulted in leachate con-
centrations below the STLC of 5 ppm. Leachate
concentrations of chromium, like PCP, increased
following the STC treatment based on the
CALWET, resulting in negative percent reduc-
tions ranging from -205 to -375 percent. Chro-
mium leachate concentrations, however, re-
mained below the STLC limit of 560 ppm.
Copper concentrations were slightly reduced
upon treatment; however, only Batch 1 was
brought below the STLC of 25 ppm for the
treated CALWET leachates. Batch 3 was below
this threshold prior to treatment. Overall, per-
cent reductions for copper ranged from 2 to 22
percent.
TCLP-Cage Test (Modified TCLP)
Table B-6 depicts TCLP-Cage analyses and
compares the results with post-treatment TCLP
and TCLP-Distilled Water tests for arsenic,
chromium, copper, and PCP. The TCLP-Cage
test determines the amount of constituents
teachable from a monolith of solidified/
stabilized waste. This leach test is a modified
form of the TCLP test in that the sample is
subjected to an acidic leaching medium but is
not crushed or ground prior to leaching. Other-
wise, the waste is leached in an identical manner
as in the standard TCLP.
One would expect greater leaching under
standard TCLP test conditions due to the in-
creased exposed surface area resulting from
crushing the solidified waste; however, this was
not typically the case for metals. For the metals,
all but three cases showed higher concentrations
in the TCLP-Cage leachate when compared to
the TCLP; however, the results were highly
variable especially for chromium and copper
where standard deviation values exceeded mean
values. For PCP, on the other hand, the lowest
leachate concentrations were obtained for the
TCLP-Cage test in all batches, except Batch 3
for which PCP was not detected in both the
TCLP and TCLP-Cage tests. All TCLP, TCLP-
Cage, and TCLP-Distilled Water values for the
treated waste samples were well below the regu-
latory levels for the TCLP except for copper for
which regulatory levels have not yet been
established). However, raw waste samples were
also well below these levels.
ANS 16.1 Test
The ANS 16.1 leach test simulates leaching
of a stabilized waste with rapidly flowing ground
water by using a static sequential leaching meth-
od. A 10-week modification of the ANS 16.1
leach test was used to approximate leaching from
intact solidified waste samples using demineral-
ized water flowing around the waste samples (the
initial leach periods were lengthened because
previous experience indicated that solidified
matrices were barely wetted during the stan-
dard ANS 16.1 leach periods).
Results of the leachate analyses are presented
in Table B-7. Only negligible amounts of each
of the three selected metals — arsenic, chromi-
um, and copper -- were detected in the leachates
after each test period. Except for chromium
after the second test period, all metal values
were at or near the minimum reporting limits.
PCP results were slightly higher than minimum
reporting limits, although they were still very
low. As part of the ANS 16.1 leachability test,
the leachability index (LI) is recommended as a
standard method for evaluating solidified waste
forms. The leachability index is defined as:
"•Hi?-
where De is the effective diffusion coefficient;
calculation of De is further discussed in the STC
TER. This index is used to compare the relative
mobility of contaminants on a uniform scale.
This scale varies from very mobile for a value of
5 to immobile for values of 15 or greater. The
ANS 16.1 leachability index was calculated from
the leach results for arsenic, chromium, copper,
and PCP. The values of the leachability indices
are as follows:
73
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Table B-6. Results of TCLP, TCLP-Cage, and TCLP-Distilled Water
for Treated Wastes
Constituent
Arsenic
Chromium
Copper
PCP
Batch
1
3
4
5
1
3
4
5
1
3
4
5
1
3
4
5
Concentrations (ppm)*
TCLP
0.086 ± 0.055
0.101 ± 0.030
0.875 ± 0.153
0.548 ± 0.095
0.245 ± 0.005
0.187 ± 0.012
0.276 ± 0.010
0.320 ± 0.034
0.090 ± 0.005
0.075 ± 0.008
0.103 ± 0.005
0.062 ± 0.012
3.42 ± 1.50
<0.250
5.52 ± 0.32
0.804 ± 1.17
TCLP - Cage
0.327 ± 0.025
0.117 ± 0.011
0.740 ± 0.201
0.253 ± 0.040
0.607 ± 0.240
0.140 ± 0.010
0.660 ± 0.819
0.573 ± 0.637
1.61 ± 0.689
0.096 ± 0.004
1.43 ± 2.23
1.80 ± 2.29
1.190 ± 1.70
<0.250
0.167 ± 0.072
0.074 ± 0.001
TCLP
Distilled Water
<0.01
<0.01
0.011 ± 0.001
0.012 ± 0.001
<0.05
<0.05
0.056 ± 0.006
0.079 ± 0.003
0.0303 ± 0.0008
0.0302 ± 0.0004
0.0542 ± 0.0018
0.031 7 ± 0.0014
3.98 ± 1.770
0.58 ± 0.083
3.87 ± 0.459
3.05 ± 0.846
a = Results reported as the mean and standard deviation of six samples.
Table B-7. ANS 16.1 Leachate Analyses for STC-Treated Waste (Batch 3)
Constituent
Arsenic
Chromium
Copper
PCP
PH
Concentrations (ppm)*
Day 14
<0.004
<0.01
0.022 ± 0.003
0.235 ± 0.094
11.6
Day 28
0.004 ± 0.001
0.046 ± 0.070
<0.02
0.125 ± 0.038
11.6
Day 42
<0.004
0.019 ±0.012
0.027 ± 0.010
0.125 ± 0.034
11.0
Day 56
<0.004
0.0100 ± 0.0004
<0.02
0.127 ± 0.030
11.2
Day 7ft
<0.004
<0.01
<0.02
0.104 ± 0.020
11.0
a = Results reported as mean and standard deviation of three samples plus a duplicate.
74
-------
Arsenic
Chromium -
Copper
PCP
LI = 12.2
LI= 11.0
LI = 10.9
LI= 10.8
These values are well above the Nuclear
Regulatory Commission's minimum leachability
index standard of 6. However, the standard for
this index has no specific basis in terms of
human or environmental risk or toxicity and
therefore is not sufficient to guarantee that the
products of the process are protective of human
health and the environment if they are placed in
a landfill.
Oil and Grease Analysis
Oil and grease extracts were analyzed for
both raw and treated wastes, and the results are
reported in Table B-8. Calculated percent
reductions ranged from 32 to 52 percent. Al-
though the STC treatment process was not espe-
cially effective in reducing the amount of ex-
tractable oil and grease in the SPT waste, the
presence of small quantities (< 2 percent) of oil
and grease did not appear to adversely affect the
solidification of the waste as determined by the
petrographic observations (discussed below).
pH, Eh, Loss on Ignition, and Neutralization
Potential
Additional chemical waste characterization
consisted of determining the pH, Eh, loss on
ignition, and neutralization potential for both
raw and treated wastes. These results are sum-
marized in Table B-9. Results for pH, Eh, and
loss on ignition are also presented for STC's
solidified reagent mixture, sand, and water
additives (Table B-10).
Raw waste samples were slightly acidic to
neutral with pH values ranging from 6.3 to 7.1.
Treated wastes were very basic with pH values
of 12.5 to 12.6. The sand and water additives
had slightly basic characteristics with a pH of 8.6
and 8.0 respectively, and the STC reagent mix-
ture was very basic with a pH of 12.5.
Oxidation-reduction potential, measured in
terms of Eh (millivolts), ranged from 389 to 421
for the raw waste, with slightly lower values of
366 and 368 for sand and water additives respec-
tively. The STC reagent mixture and treated
wastes reveal much lower Eh values of 144 and
162.7 to 174.3, respectively. This decrease in the
reduction/oxidation potential indicates a less ox-
Table B-8. Oil and Grease Analysis
Constituent
Oil and Grease
Batch
1
3
4
5
Concentrations (ppm)
Raw Waste"
10,667 ± 577
11,667± 557
19,000 ± 1,000
19,667 ± 577
Treated Waste*
3,733 ± 252
3,200 ± 200
7,300 ± 608
7,400 ± 361
Percent Reduction*
38.4 (30.5 - 45.5)
51.6 (45.9-56.8)
31.8 (22.0-40.6)
34.3 (29.0 - 39.3)
a = Results reported as the mean and standard deviation of three samples.
b = Percent Reduction = fl - (1 * Additb*s Ratio) * Concentration of Treated Waste] x 1(X)
[ Concentration of Saw Waste \
The low end of the percent reduction range was calculated by subtracting the standard deviation from the raw waste
mean and adding the standard deviation to the treated waste mean to produce a worst-case value. The high end of the
percent reduction range was calculated by adding the standard deviation to the raw waste mean and subtracting the
standard deviation from the treated waste mean to produce a best-case value.
c = The additives ratio is the weight of additives, including water ofhydration, divided by the weight of wastes. Values are
0.761, 0.764, 0.776, and 0.746 for Batches 1, 3, 4, and 5, respectively.
75
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Table B-9. Analytical Results for pH, Eh, Loss on Ignition, and Neutralization Potential
for Raw and Treated Waste
Analysis
pH (pH units)
Eh (mV)
Loss on Ignition (%)
Neutralization Potential
(meq/gram)
Batch
1
3
4
5
1
3
4
5
1
3
4
5
1
3
4
5
Raw Waste*
7.1
6.9
6.3
6.9
388.7
393.3
421.0
399.3
6.87
6.27
7.70
8.33
0.14
0.13
0.12
0.15
Treated Waste*
12.5
12.6
12.5
12.5
162.7
164.7
165.7
174.3
24.7
24.3
26.1
26.2
3.7
3.7
3.6
3.7
a = Values are averages of duplicate analyses.
Table B-10. pH, Eh, Loss on Ignition and Neutralization Potential for Sand, Water,
and STC Reagent Mixture
Analysis
pH (pH units)
Eh (mV)
Loss on Ignition (%)
Neutralization Potential (meq/gram)
Sand
8.6
366
12.2
—
Water'
8.0
368
—
—
Reagent Mix-
ture
12.5
144
17.6
3.7
a = Values are averages of duplicate analyses.
76
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idizing environment as a result of treatment.
Loss on ignition determines the weight loss
of a sample that has been ignited in a muffle
furnace at 950°C. The result represents total
moisture (including water of hydration) and
carbon content of a cementitious sample. Per-
cent loss on ignition values range from 6.27 to
8.33 percent for the raw waste with the sand
value at 12.2 percent loss. The STC reagent
mixture lost 17.6 percent upon ignition, while
the treated wastes had values of 24.3 to 26.2
percent loss.
The neutralization potential of cementitious
reagents and treated wastes, reported in terms of
milliequivalents (meq) per gram, measures the
amount of neutralizers present in the material.
This measurement is found by treating a sample
with known amount of standardized hydrochlo-
ric acid, heating to assure complete reaction, and
titrating with a standardized base. The result is
expressed in calcium carbonate equivalents and
represents tons of calcium carbonate available to
neutralize 1,000 tons of material, based on the
assumption that an acre plow-layer contains
2 million pounds of soil. Neutralization poten-
tial values for the raw waste ranged from 0.12 to
0.15 meq/gram. The reagent mixture and treat-
ed waste both had higher average values of
3.7 meq/gram.
Soil Physical Characteristics
Raw waste physical characterization consist-
ed of mean particle size, moisture content, and
bulk density measurements. These results are
presented in Table B-11. Post-treatment physi-
cal characteristics are presented in Tables B-12
through B-14 and include moisture content, bulk
density, permeability, unconfined compressive
strength, and wet/dry and freeze/thaw weather-
ing.
The mean particle size of the raw waste
ranged from approximately 0.06 to 0.07 mm
indicating a very-fine sand texture. The added
coarse sand had a mean particle size of 0,65 mm.
Moisture content of the raw waste was low
ranging from 3.9 to 5.8 percent with the sand at
6.1 percent. Moisture content of the treated
wastes, although also low, varied more — from
1.9 to 9.7 percent with up to 7.7 percent stan-
dard deviation. The treated reagent mixture had
a moisture content of 4.1 percent.
Average bulk densities ranged from 1.42 to
1.54 g/cm3 for the raw waste. Treated waste
samples show slightly higher average bulk densi-
ties ranging from 1.55 to 1.62 g/cm3. The treat-
ed reagent mixture had an average bulk density
of 1.92 g/cm3. Calculated volume changes based
on these data show volume increases ranging
from approximately 59 to 75 percent.
Falling-head permeability rates were deter-
mined using a triaxial cell by measuring changes
of water volume over time under controlled
temperature and pressure conditions. Average
permeability values for the treated waste ranged
from 0.8 x 10'7 to 1.7 x 10'7 cm/sec. The solidi-
fied reagent mixture had an average permeability
of 1.5 x 10'7 cm/sec. These values are of the
same order of magnitude as the permeability
requirements for hazardous waste landfill soil
barrier liners of 10'7 (40 CFR part 264, subpart
N).
Unconfined compressive strength (UCS) is
the load per unit area, measured in pounds per
square inch (psi), at which an unconfined solid
cylindrical sample fails a compression test.
Average UCS values for the treated wastes
ranged from 259 to 347 psi. These values are
significantly below the American Society for
Testing and Materials (ASTM)/American
Concrete Institute (ACI) minimum required
unconfined compressive strength of 3,000 psi for
the construction of sidewalks (ASTM, 1991).
However, the measured UCS values are well
above the EPA minimum guideline of at least 50
psi for hazardous waste solidification (U.S. EPA,
1986).
Wet/dry and freeze/thaw weathering tests
assess the structural integrity of treated wastes
when exposed to adverse weather conditions.
Tables B-13 and B-14 present the cumulative
corrected relative weight loss percentages over a
period of 12 days for the treated waste as well as
the solidified reagent mixture. These data show
less than 1 percent relative weight loss, indicat-
ing good structural stability of the solidified
waste for the time frame studied. Visual inspec-
tion of the samples also verified that samples
remained intact throughout the 12-day test cycle.
However, long-term extrapolation of such limit-
ed weathering data may yield erroneous conclu-
sions about the stability of the STC solidified
waste.
77
-------
Table B-ll. Physical Characteristics of Raw Wastes and Sand
Batch
1
3
4
5
Sand
Mean Particle Size
(mm)*
0.063 ± 0.006
0.063 ± 0.003
0.074 ± 0.010
0.073 ± 0.003
0.65
Moisture Content
(%)**
5.8 ± 1.6
5.7 ± 1.7
4.2 ± 2.3
3.9 ± 2.5
6.1 ±2.5
Bulk Density"
(g/cmj)
1.42 ± 0.13
1.54 ± 0.17
1.54 ± 0.17
1.54 ± 0.17
—
a = Results reported as the mean and standard deviation of three or more samples.
b = Calculated from weight loss at 105 °C; moisture content = (wet weight ~ *** weigM> x 100.
dry weight
Table B-12. Physical Characteristics of STC-Treated Wastes and Reagent Mixture
Batch
1
3
4
5
RM
Moisture Content
(%)-"
2.6 ± 0.38
1.9 ± 0.25
9.7 ± 7.65
8.8 ± 3.81
4.1 ± 2.82
Bulk Density
(g/cm1)"
1.57 ±0.03
1.55 ± 0.02
1.58 ± 0.01
1.62 ± 0.04
1.92 ± 0.02
Permeability;
(cm/sec)*
1.7 x 10'7± 0.40 x 10'7
1.5 x 10'7±0.98 x 10'7
0.9 x 10'7±0.41 x JO'7
0.8 x 1Q-7±0.47 x 1C'7
1.5x 10'7±0.27 x 10'7
ITCS
(psi)"
301 ± 162
278 ± 20
259 ± 65
347 ± 65
682 ± 144
RM = Solidified reagent mixture
a = Results reported as the mean and standard deviation of three or more samples.
b = Calculated from weight loss at 60 °C; moisture content =
Wei8ht ~ ^ weight) x
dry weight
78
-------
Table B-13. Wet/Dry Weathering of STC-Treated Wastes
Batch
1
3
4
5
EM
: Cumulative Corrected Relative Weight Lou (X)
1
0.03
0.00
0.02
0.03
0.02
3
0.04
-0.01
0.01
0.02
0.02
9
0.02
-0.04
-0.01
0.02
0.04
*
0.01
-0.05
-0.01
0.01
0.04
6
0.01
-0.06
-0.05
-0.02
0.02
«
0.00
-0.08
-0.06
-0.03
0.02
r
-0.01
-0.08
-0.09
-0.07
0.00
8
-0.02
-0.10
-0.13
-0.08
0.001
9
-0.01
-0.14
-0.14
-0.11
-0.01
10
-0.03
-0.16
-0.17
-0.13
-0.01
11
-0.04
-0.18
-0.19
-0.16
-0.02
12
-0.04
-0.21
-0.20
-0.17
-0.02
RM = Solidified reagent mixture
Table B-14. Freeze/Thaw Weathering of STC-Treated Wastes
Batch
1
3
4
5
RM
Cumulative Corrected Relative Weight Low (X)
1
0.00
-0.02
-0.02
0.00
-0.03
3
0.01
-0.05
-0.03
-0.02
-0.05
«
0.01
-0.04
-0.04
-0.03
-0.04
4
0.03
-0.05
-0.03
-0.03
-0.04
6
0.02
-0.05
-0.04
-0.05
-0.01
«
0.04
-0.04
-0.05
-0.05
0.03
T
0.05
-0.04
-0.07
-0.07
0.04
8
0.04
-0.01
-0.10
-0.08
0.07
9
0.04
-0.03
-0.09
-0.08
0.09
10
0.04
-0.02
-0.05
-0.07
0.15
11
0.06
-0.01
-0.04
-0.08
0.18
13
0.09
0.02
-0.01
-0.09
0.22
RM = Solidified reagent mixture
Petrographic Analyses
Contaminated soils and solidified samples
from each of the individual test batches includ-
ing the STC reagent mixture were examined
using optical microscopy, scanning electron mi-
croscopy (SEM), X-ray diffraction (XRD), and
Fourier transform infrared spectroscopy (FTIR)
techniques.
Petrographic observations of the materials
provided information on the homogeneity of
mixing, distribution of the matrix, and charac-
teristics of the microstructure. Raw waste
samples consisted mainly of very-fine grained
(<0.2 mm) quartz, feldspars (potassium feldspars
and plagioclase), hornblende, clay, mica, and
granite pebbles up to 10 mm diameter. Wood
fragments and other organic debris were ob-
served in small amounts. Clumps of clay-sized
material appeared to be held together by an oily
substance, and larger particles typically had
shiny coatings of oil.
The solidified wastes and reagent material
were well consolidated, with air voids estimated
at 3 to 7 percent. The black opaque binder
material was moderately soft, evenly distributed
with a moderately tight binder-aggregate bond.
Carbonation of the binder around air voids
indicated a reaction between calcium hydroxide
(portlandite) and air. In addition, small amounts
of greenish-brown glassy slag and traces of
residue portland-cement clinker were observed.
The soil-binder system appeared to be well
mixed based on distribution and size of soil
aggregates (2 to 4 mm diameter). Clumps with
diameters up to 1 cm were typically surrounded
by a tar-like rim. Faint layering was observed in
several samples.
79
-------
A summary of the petrographic observations
is presented in Table B-15. Batch 1 included a
quality control sample (1-QC). The binder
distribution for both samples from Batch 1 was
nonuniform. In addition, one sample from Batch
1 was underconsolidated compared to the other
batch samples that were all well consolidated.
Batch 1 was the only batch analyzed that was not
sieved as part of the pretreatment process.
Results of XRD analyses are presented in
Table B-16. Conclusions from the petrographic
analyses concerning the binder and soil materials
were confirmed by the XRD examination.
These analyses also indicate that the STC process
used predominantly silica and potassium-alumi-
num silicates in addition to calcium hydroxide
and sulfates to form the binding agent.
SEM analyses indicated relatively good
binder-to-aggregate bonding except in rare cases
where oily particle coatings prevented adequate
bonding. However, the quality of the surround-
ing binder sufficiently macroencapsulated such
particles. The following elements were com-
monly detected using an energy dispersive X-ray
(EDX) fluorescence probe in conjunction with
the SEM: calcium, silicon, iron, aluminum,
potassium, and chlorine, with minor amounts of
sulfur, arsenic, chromium, titanium, and copper.
Elemental maps of heavy metal contamination
suggest good containment of the metals; mixing
of binder and waste followed by consolidation
did not appear to cause migration of metals from
contaminated particles into the surrounding
material.
FTIR analyses showed that organic materials
were volatilized at 200°C and 300°C in the raw
waste samples. There was no evidence for the
presence of condensed organic compounds below
200°C or above 300°C. The total amount of
organic materials volatilized from these samples
was approximately 1 to 2 percent. Substantial
amounts of adsorbed water were also released
from the raw waste samples upon heating.
Infrared analysis identified the organic materials
volatilized from the raw wastes as a mixture of
aliphatic and aliphatic-substituted aromatic
hydrocarbon compounds. The spectra showed
evidence for the presence of carboxylic acid
groups, and nitrogen-hydrogen bonds, present as
amine or amide groups. This composition is
consistent with the residue from a heavy oil,
such as diesel fuel. PCP was not specifically
detected in the infrared spectra of the organic
pyrolyzates in the raw waste; however, a mini-
mum concentration of 10,000 ppm (1 percent)
PCP is required for detection using FTIR analy-
ses. Average TWA concentrations of PCP in the
raw waste did not exceed this minimum concen-
tration. In addition, PCP may be strongly ad-
sorbed to the soil and therefore all of the PCP
present in a sample may not be released upon
heating. More aggressive chemical extraction
procedures are required to release all of the PCP.
Additional analyses to quantify the amount of
PCP volatilization at varying temperatures are
presented in the STC TER.
Pyrolysis of the treated wastes showed almost
no evidence for the release of organic species,
from either large chunks (3/8-inch diameter) or
processed powder (<150 mesh). One exception
yielded a small amount of primarily aliphatic
hydrocarbon species, after pyrolysis of the
sample in chunk form at 400°C.
Long-Term Tests
Long-term chemical monitoring of the STC-
treated waste showed whether the potential
leachability of TCLP extracts for metals and
TWA for PCP of the treated waste were affected
by aging. Results for analyses of 6- and 18-
month cured samples are presented in Table B-
17. Averages of six samples for the 6-month
analyses and four samples for the 18-month
analyses are compared to both the raw waste
sample analyses and the treated, 28-day cured
sample analyses. Percent reductions for each of
the sample leach periods have also been included.
Additional long-term (18-month) weathering
studies from exposed monoliths of the STC-
treated waste are discussed in the STC TER.
In all but three cases, the TCLP extracts of
the 6-month cured samples showed an average
increase in contaminant concentration of 79
percent from the 28-day sample leachates.
Arsenic concentrations in Batches 4 and 5 were
slightly lower in the 6-month tests; however,
high analytical variability for these two batches
indicates that the arsenic content in the leachate
of the 6-month cured samples were similar to
that of the 28-day cured sample leachate. The
TCLP leachate of the 18-month cured samples
for arsenic showed slight decreases from the 28-
day and 6-month leachate concentrations.
Percent reductions improved over the 18-month
80
-------
rented Wastes (Batches)
F
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Calcium hydroxide
Black pigment
Isotropic glass
Portland cement
Calcium hydroxide
Black pigment
Isotropic glass
Portland cement
alcium hydroxide
lack pigment
otropic glass
Drtland cement
U ffl £ a.
.a
*4
g
VI
§,
£ J
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feldspar, potassium
feldspar, hornblende,
clay, biotite, wood
fragments, misc.
organic debris, paper
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feldspar, hornblende,
clay, biotite, wood
fragments, misc.
organic debris, paper
Quartz, plagioclase
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feldspar, hornblende,
clay, biotite, wood
fragments, misc.
organic debris, paper
uartz, microcline;
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81
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(Batches)
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period to range from 82 to 93 percent.
Chromium concentrations in the leachate of the
18-month cured samples showed slight to
moderate increases with time, resulting in even
greater negative percent reductions. Copper also
showed very slight to moderate increases in
TCLP-extract concentrations over time.
Average percent reductions for copper dropped
from 96 percent reduction after the initial 28-
day curing period to 78 percent reduction after
18 months.
TWA of PCP after the 6-month period
showed greater extractable concentrations for
Batches 4 and 5 than after the initial 28-day
period. Extractable concentrations of PCP
generally remained consistent for Batches 1 and
2 over this time period. The 18-month analyses
showed decreased concentrations of PCP in the
treated waste; however, Batch 5 continued to
show considerable analytical variability. Percent
reductions following the 18-month period
averaged 96 percent.
Table B-18 shows additional long-term ion-
speciation analyses for chromium (VI) relative to
total chromium in both raw and treated waste
TCLP-Distilled Water extracts for Batch 5. The
wastes were analyzed 8 months after the demon-
stration, revealing greater teachable quantities
for both chromium (VI) and total chromium in
the treated waste. The 8-month leachate con-
tained approximately four times the quantity of
total chromium compared to the 28-day TCLP-
Distilled Water leachate, and almost three times
as much total chromium as the initial raw waste
sample, again indicating that STC's solidifica-
tion/stabilization treatment process does not
reduce the leaching of total chromium over the
long term. Increased quantities of the ion-
species chromium (VI) in the 8-month leachate
compared to the raw waste values indicate that
STC's treatment process may result in the oxida-
tion of chromium, thereby rendering it more
mobile. The long-term results are, however, still
within the federal regulatory threshold level for
chromium.
The physical strength of the STC-treated
waste was evaluated after 18 months using the
unconfined compressive strength (UCS) test.
Results reported in Table B-19 show an average
increase in strength of 71 percent over the 18-
month period. Additional long-term analyses
scheduled for 36 months following the demon-
stration will include solidification monitoring
using unconfined compressive strength measure-
ments and petrographic analyses as well as
stabilization monitoring using chemical and leach
tests. The final results for the long-term moni-
toring will be available from EPA upon comple-
tion.
Conclusions
The STC immobilization technology reduced
the short-term mobility and teachability of
arsenic and copper as measured by the TCLP and
the TCLP-Distilled Water methods. The solidi-
fication/stabilization treatment process was also
successful in reducing the mobility and potential
leachability of PCP as measured by the TCLP-
Distilled Water test and TWA. Leachability was
not effectively reduced for chromium as mea-
sured by any of the leaching procedures, except
possibly the ANS 16.1 test. However, chromium
was not targeted for treatment in this demonstra-
tion and no specific additives were included to
treat chromium. In addition, the CALWET leach
test showed very inconsistent trends for all of the
analytes.
Based on California state regulatory levels
for legal disposal as nonhazardous waste in
landfills, the STC treatment process did not
consistently meet total (TTLC) or solubility
(STLC) threshold limit concentration require-
ments. CALWET leach results were both below
and above California's STLC levels for arsenic,
copper, and PCP. TWA for chromium and
copper were well below California's TTLC;
however, TWA for arsenic and PCP were above
California total threshold requirements for both
the raw and treated wastes. Federal leach crite-
ria could not be adequately evaluated since
TCLP concentrations of arsenic, chromium, and
PCP were below federal TCLP regulatory levels
in both the raw and treated wastes.
Preliminary evidence suggests that the homo-
geneity and structural characteristics of the STC-
treated waste would resist the normal effects of
weathering. Low unconfined compressive
strengths of the treated waste, although above
minimum levels for disposal in landfills, were
not sufficient for construction purposes. Addi-
tional tests would be needed to determine the
appropriate reagent mixture necessary to meet
construction requirements if desired. Initial
85
-------
Table B-18. Long-Term (8-month) Chromium Analysis -- TCLP-Distilled Water (Batch 5)
Constituent
Chromium (VI)
Total Chromium
Raw Waste
(ppm)
<0.01
<0.01
0.13
0.12
Treated Waste
(ppm)
0.15
0.18
0.31
0.32
Table B-19. Long-Term Physical Tests
Batch
1
3
4
5
Unconfined Compressive Strength (psi)"
28-day
301 ± 162
278 ± 20
259 ± 65
347 ± 65
18- month
958 ± 63
763 ± 19
1,017 ± 73
1,375 ± 26
a - Results reported as mean and standard deviation of three samples.
6-month TCLP-extract and TWA showed in-
creased concentrations of contaminants re-
leased from the treated waste. Eighteen-
month analysis showed improved percent re-
ductions for arsenic, averaging 88 percent
reduction, and PCP averaging 96 percent re-
duction. Chromium and copper concentrations
showed slight to moderate increases in the
TCLP-extracts over time. Unconfined com-
prehensive strengths increased an average of 71
percent. The long-term stabilization and
solidification effectiveness of the STC immo-
bilization technology must still be monitored
and assessed at the end of the planned 3-year
period.
References
American Society for Testing and Materials,
1991. Annual Book of ASTM Standards.
ASTM Philadelphia, PA.
CDM Federal Programs Corporation, 1988a.
Final Remedial Investigation Report for the
Selma Pressure Treating Site, Selma, Califor-
nia.
CDM Federal Programs Corporation, 1988b.
Feasibility Study Report for the Selma Pres-
sure Treating Site, Selma, California.
CDM Federal Programs Corporation, 1989. Pre-
Remedial Design Soil Boring Report for the
Selma Pressure Treating Site, Selma, Califor-
nia.
Engineering-Science, Inc., 1991. Draft Data
Summary for the STC SITE Demonstration.
U.S. EPA, 1986. Prohibition on the Placement
of Bulk Liquid Hazardous Waste in Landfills,
Statutory Interpretative Guidance.
EPA/530/SW86/016.
U.S. EPA, 1990. STC SITE Program Demon-
stration Plan, Volume III: Quality Assurance
Project Plan.
86
-------
Appendix C
Case Studies
-------
Appendix C
Table of Contents
Section
Introduction 89
Case Study C-l Tacoma Tar Pits, Tacoma, Washington 90
Case Study C-2 Purity Oil Sales Site, Fresno, California 109
Case Study C-3 Kaiser Steel Corporation, Fontana, California 115
Case Study C-4 Brown Battery Breaking Superfund Site, Reading, Pennsylvania .... 128
Case Study C-5 Lion Oil Company, El Dorado, Arkansas 129
References 136
List of Tables
Table Page
C-l-1 Treatability Test Results for Raw and Treated Wastes from the Tacoma
Tar Pits (Tar Pit) 92
C-l-2 Treatability Test Results for Raw and Treated Wastes from the Tacoma
Tar Pits (Tar Boils) 93
C-l-3 Treatability Test Results for Raw and Treated Wastes from the Tacoma
Tar Pits (North Pond) 95
C-l-4 Treatability Test Results for Raw and Treated Wastes from the Tacoma
Tar Pits (South Pond) 97
C-l-5 Treatability Test Results for Raw and Treated Wastes from the Tacoma
Tar Pits (Auto Fluff) 99
C-1-6 STC-Treated Waste Composition 100
C-l-7 STC Raw Waste Analytical Results 103
C-l-8 TCLP Analytical Results for STC-Treated Wastes 105
C-l-9 Physical Test Results of STC-Treated Waste 107
C-2-1 Analytical Results for Purity Waste Ill
C-3-1 Analytical Results for KSC Waste 116
C-3-2 Summary of Physical Analysis of KSC Waste 127
C-4-1 Lead Analyses for Untreated Brown Battery Plant Soils 128
C-4-2 Lead Analyses for Treated Brown Battery Plant Soils 128
C-5-1 Analytical Results of Metal Concentrations from the Lion Oil Refinery
Treated Sludge 130
C-5-2 Analytical Results of Volatile and Semivolatile Organic Compounds from
the Lion Oil Refinery Treated Sludge 131
C-5-3 Solidification Results for the Lion Oil Refinery Sludge 132
88
-------
Appendix C
Case Studies
Introduction
This appendix summarizes case studies on
the use and performance of Silicate Technology
Corporation's(STC's)immobilizationtechnology.
The information available for these case studies
pertains mainly to detailed analytical data ob-
tained from preliminary bench-scale treatability
studies. The Tacoma Tar Pits case study repre-
sents both a bench- and pilot-scale treatability
study, whereas the remaining four are bench-
scale treatability studies. The bench-scale
studies relating to the Tacoma Tar Pits, Purity
Oil, and Kaiser Steel sites were performed in
conjunction with the SITE demonstration
program. Very little information was provided
pertaining to system performance or costs. The
following five case studies are summarized in
this appendix:
Case Study
Facility and Location
C-l
C-2
C-3
C-4
C-5
Tacoma Tar Pits, Tacoma, Washington
Purity Oil Sales Site, Fresno, California
Kaiser Steel Corporation, Fontana, California
Brown Battery Breaking Superfund Site, Reading, Pennsylvania
Lion Oil Refinery, El Dorado, Arkansas
89
-------
Case Study C-l
Tacoma Tar Pits
Tacoma, Washington
The Tacoma Tar Pits, Joseph Simon and
Sons, Inc., site in Tacoma, Washington was
initially considered as a potential demonstration
site for evaluating STC's solidification/stabili-
zation technology under the Superfund Innova-
tive Technology Evaluation (SITE) program.
This site covers approximately 30 acres and is
located between the Puyallup River, the City
Waterway, and Wheeler-Osgood Waterway in a
predominantly industrial area of Tacoma, Wash-
ington. The area of sediment deposited as the
Puyallup River delta is interfingered with ma-
rine sediments of Commencement Bay. These
sediments form a tidal marsh/tidal flat with
shallow, meandering streams.
Industrialization of the site and surrounding
area began as early as the turn of the century,
resulting in fill and dredge activity to develop
the area for construction. A variety of indus-
tries have occupied the area, including railroad
(Burlington Northern and Union Pacific) and
meat packing operations. In 1924 a coal gasifi-
cation plant was built on the site and operated
by a number of entities. Construction of a
natural gas pipeline to Tacoma in 1956 rendered
the gasification plant obsolete. Waste tar con-
tainment structures were left in place below
ground when the plant was demolished in 1965-
1966. Since 1967, Joseph Simon and Sons, Inc.,
a metal recycler, has operated at the site.
The primary sources of contaminants at the
site were tars from the old coal gasification plant
as well as metals and organics (including PCBs)
from the battery and transformer scrapping and
automobile shredding by Joseph Simon and Sons,
Inc. To a lesser degree, run-off from the meat
processing facility and railroad facilities may
have also affected the site.
Historical photographs indicate that coal tars
once covered most of the southern and western
portions of the site; however, recent access to
coal tars has only been at the residual tar pit, tar
boils, and the north and south ponds. Most of
the area between the ponds at the far western
side of the site and the tar pit in the southeastern
portion of the site has been covered with shred-
ded automobile interiors (auto fluff).
Typically, concentrated contaminants were
present at the ponds as a non-aqueous phase
liquid (NAPL) that had a strong creosote odor
and were predominantly polycyclic aromatic
hydrocarbons (PAH). Hazardous constituents
present in the coal tars at the site included
benzene, toluene, xylene, styrene, phenols,
naphthalenes, dibenzofuran, methylene chloride,
and chloroform. In addition to these, metals
such as lead, arsenic, cadmium, aluminum, iron,
chromium, and zinc were present in elevated
concentrations in the auto fluff and subsurface
soils.
The auto fluff covered much of the original
tar pit and apparently underlies the north and
south ponds. Auto fluff material consisted of
shredded automobile interiors and had the tex-
ture and appearance of a silty-sandy soil mixed
with metal fragments, shredded foam, rubber,
wire, plastic, ceramic fragments, and other
unidentifiable objects. Typically contaminants
in the auto fluff included heavy metals and
PCBs.
The most heavily contaminated areas of the
site included those covered by auto fluff, the
residual tar pit, tar pit boils, and the north and
south ponds. During a preliminary sampling
visit in October 1988, the north and south ponds
both contained water. The substrate of the
90
-------
ponds consisted of a tarry sediment mixed with
pieces of auto fluff. Disturbance of the sedi-
ments produced an upwelling of concentrated
NAPL from the pond bottom. The NAPL may
have been mixed with animal process waste from
the adjoining meat processing property as indi-
cated by the fatty coating on sediments. Tar
collected from the tar pit was much thicker than
the pond sediment, and had the appearance of
asphalt. The tar pit area also had a strong creo-
sote odor, as did the tar boil area. Tar from the
tar boil area was very thick, viscous, and often
mixed with a variety of metal, ceramic debris,
and some native soils.
In January 1989, STC conducted bench-scale
treatability testing for the Tacoma Tar Pits site
on wastes from the tar pit, the tar boils, the
north and south ponds and the auto fluff areas.
EPA's SITE contractor (PRC) performed sam-
pling and analysis, including Toxicity Character-
istic Leaching Procedure (TCLP), TCLP-Cage,
Extraction Procedure (EP), and total waste
analysis (TWA). Results for the chemical
analyses of volatile and semivolatile organics as
well as metals for both the raw and treated
wastes are presented in Tables C-1 -1 through C-
1-5. Percent reductions were calculated by using
0.6 as the "additives ratio" for all reagents added
during treatment, excluding water. The
additives ratio was used to calculate the percent
reduction using the following formula:
Percent Reduction =
1 - (1 * Additives Ratio) X Concentration of Treated Waste
Concentration of Raw Waste
In general, STC's treatment process yielded
reductions in TCLP leachate concentrations for
up to five volatile organics, up to eleven semi-
volatile organics, and up to seven metals from
the combined sites at the Tacoma Tar Pits site.
The greatest percent reductions for volatile
organics included benzene, styrene, toluene, and
total xylenes. However, the treatability testing
was not conducted in a manner to capture and
quantify volatile organics that may have been
lost due to mixing during the treatment process
and curing. Semivolatile organics that showed
the greatest reductions in TCLP leachate con-
centrations included bis(2-ethylhexyl)phthalate,
phenol, 2-methylphenol, 4-methylphenol, and
2,4-dimethylphenol. The greatest metal reduc-
tions were observed for zinc, lead, nickel, cop-
per, and cadmium.
EP yielded reductions in leachate
concentrations for up to ten semivolatile organics
and four metals. Volatile organics were not
analyzed using this leach test method.
Semivolatiles with the greatest leachate concen-
tration reductions included 2-methylphenol,
phenol, and 2,4-dimethylphenol. The greatest
metal reductions in leachate concentrations were
observed for zinc, nickel, lead, and copper.
Finally, TWA yielded reductions for up to 13
semivolatile organics, five volatile organics
(volatiles may have been airstripped) and seven
metals. The greatest percent reductions in
semivolatile concentrations were observed for
fluorene, and 2,4-dimethylphenol. Volatile
organics, except for benzene, generally yielded
percent reductions in total concentration of less
than 60 percent. Copper yielded the greatest
metal percent reduction based on TWA.
In October, 1990, a pilot-scale field study
was also performed by STC at the Tacoma Tar
Pits site. The field study included treatment of
37 batches, including 27 different blends, 9
duplicates, and 1 blank batch. Three different
wastes (tar, auto fluff, and contaminated soil)
were treated at low, medium, and high reagent
dosages (approximately 15%, 25%, and 30% on a
dry weight basis at 60°C) for a total of 27 test
batches.
Table C-l-6 shows the actual STC treated
waste composition, including moisture content.
These waste blends were developed during a
second bench-scale study conducted prior to the
pilot-scale field demonstration. Representative
samples of auto fluff, tar, and soil were excavat-
ed. The auto fluff and soil were passed through
a power screen for rough size fractionation and
a secondary screening step for size classification.
Auto fluff particles not passing through the
screen were shredded and added to the mixture
91
-------
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Table C-l-6. STC-Treated Waste Composition
Sample
I-L
I-MA
I-H
II-L
II-M-1
II-M-2
II-M-3
II-M-4
II-H
III-L
III-M
III-H
IV-L
IV-M-1A
IV-M-2
IV-M-3
IV-M-4
IV-H
V-L
V-M-1
V-M-2
V-M-3
V-M-4
V-H
VI-LA
VI-M
VI-H
VII- L
VII-M
VII-H
Soil
% of Dry Wt.
67.8
58.6
52.0
46.2
40.2
38.9
41.0
39.9
34.6
25.9
21.8
19.7
58.9
51.0
50.5
51.5
51.5
45.2
39.8
33.0
33.4
31.8
33.0
29.3
13.5
16.1
14.4
50.1
44.0
38.0
Fluff
% of Dry Wt.
0
0
0
19.8
17.2
16.6
17.5
17.1
14.8
38.9
32.8
29.6
0
0
0
0
0
0
19.9
16.5
16.7
15.9
16.4
14.7
37.0
32.4
28.8
0
0
0
Tar
% of Dry Wt.
0
0
0
0
0
0
0
0
0
0
0
0
6.5
5.6
5.6
5.7
5.7
5.0
6.6
5.5
5.5
5.3
5.5
4.9
6.2
5.4
4.8
12.5
10.9
9.5
S-4
Wt. %
2.7
2.3
2.1
2.6
2.3
2.2
2.3
2.3
2.0
2.5
2.2
2.0
2.6
2.2
2.2
2.2
2.2
1.9
2.6
2.2
2.2
2.1
2.1
1.9
2.5
2.1
1.9
2.5
2.2
1.9
P-27
Wt. %
13.6
23.4
31.2
13.2
23.0
22.3
23.4
22.8
29.6
12.9
21.8
29.6
13.1
22.6
22.4
22.8
22.8
30.1
13.2
22.2
22.3
21.1
22.0
29.3
12.3
21.5
28.8
12.5
21.9
28.5
Moisture Content
Wt. %
15.9
15.7
14.7
18.2
17.3
20.0
15.8
17.9
19.0
19.8
21.4
19.1
18.9
18.6
19.3
17.8
17.8
17.8
17.9
20.8
19.9
23.8
21.0
19.9
28.5
22.5
21.3
22.4
21.0
22.1
100
-------
Table C-l-6. STC-Treated Waste Composition (continued)
Sample
VIII-L
VIII-M
VIII-H
IX-L
IX-M
IX-HA
BLANK-M
Soil
% of Dry Wt.
31.2
26.7
28.7
12.0
10.7
9.3
62.9
Fluff
% of Dry Wt.
18.7
16.0
14.2
36.0
32.1
28.0
0
Tar
% of Dry Wt.
12.4
10.6
9.5
12.0
10.7
9.3
0
S-4
Wt, %
2.4
2.1
1.9
2.4
2.1
1.8
2.5
P-27
Wt. %
12.4
.21.4
28.4
12.0
21.4
28.0
25.1
Moisture Content
Wt. %
22.9
23.2
17.3
25.6
23.0
23.6
9.5
101
-------
to produce the final blends. The blended piles
of contaminated waste were sampled and ana-
lyzed for chemical contaminants including
benzene, lead, PCBs, and PAHs. Table C-l-7
presents the analytical results for the raw waste
blends. TCLP was not conducted for the raw
waste blends of this pilot-scale field study.
Approximately 1 /2-cubic-yard blocks of treated
waste were allowed to cure in wooden forms for
28 days. Sampling procedures, as well as physi-
cal and chemical analyses are described in STC's
Batch Plant Demonstration Sampling and Analy-
sis Plan.
Results of TCLP analyses of the treated
wastes are shown in Table C-l-8. These results
indicate that the STC treatment process was
generally successful in stabilizing the various soil
blends for all contaminants (PCBs, PAHs, and
lead) except benzene; however direct compari-
sons between raw and treated wastes cannot be
made because the raw waste was not evaluated
by TCLP methods. All lead values were below
detection limits of 20 ug/L. All but three of the
PCB results were below the detection limits.
Three samples did indicate leachable PCBs; two
were above the record of decision (ROD) levels
for ground water at the site boundary (0.2
Hg/L). In addition, one PCB detection was from
a replicated blend that had no PCBs detected in
the other samples. All PAH results were at least
an order of magnitude below the ROD limits for
ground water at the site boundary and many
were below detection. The TCLP data indicate
that the STC stabilized materials meet ROD
criteria for leachable lead, PAHs, and PCBs
throughout the range of blends tested in the field
study. The only contaminant that appeared to
leach at significant levels was benzene. The
leachable benzene concentration varied from
negligible amounts in samples that did not
contain tarry material to an average of
approximately 5 times the ROD established
limits for blends containing 20 percent dry
weight tarry material.
Field blank samples were also chemically
tested to determine if leachable contaminants
were contributed by sources other than the raw
waste materials. The results of the TCLP
analysis of the field blank indicated that the
vendor ingredients did not contribute to
leachable contamination.
Statistical analyses of the chemical data
reported by STC indicate that the STC process
could successfully stabilize the waste materials
for all contaminants (PCBs, PAHs, and lead)
except benzene at the Tacoma Tar Pits site with
a 95 percent confidence level. The analyses
showed that the level of additive did not have a
significant effect on the chemical stabilization of
the waste material analyzed. The level of fluff
in the stabilized material also had no effect on
the chemical stabilization. Therefore, it was
concluded that fluff concentrations up to 60
percent (dry weight) in the feed blend could be
successfully stabilized within the range of addi-
tive and tarry material tested in the pilot-scale
field study. The statistical analyses also indicat-
ed that up to 9 percent tarry material could be
stabilized with 95 percent confidence to below
the ROD criteria for benzene in ground water at
the site boundary. Dilution of benzene prior to
reaching the site boundary is likely to result in
benzene concentrations that are one-fifth of the
original concentrations based on the site hydro-
geologic conditions. Therefore, it appears that
the entire range of tarry material (up to 20
percent dry weight in the feed blank) is likely to
be successfully stabilized by the STC treatment
process.
Table C-l-9 presents results for physical
analyses including hydraulic conductivity, bulk
density, durability, and unconfined compressive
strength. All but three of the hydraulic conduc-
tivities were so low that they could not be mea-
sured. Table C-1 -9 designates the unmeasurable
hydraulic conductivities with a "low" identifier.
A statistical evaluation was not performed on the
STC hydraulic conductivity results since all of
the results achieved the established criteria of
10"7 cm/sec. Bulk densities of the STC stabilized
materials ranged from 1.6 to 2.0 g/cm3, while
durability measurements ranged from -2 to 3
percent loss in mass. Unconfined compressive
strength results ranged from 114 to 1,082 psi,
easily exceeding the minimum hazardous waste
landfill criteria of 50 psi.
102
-------
Table C-l-7. STC Raw Waste Analytical Results
Sample
I-L
I-M
I-MA
I-H
II-L
II-M-1
II-M-2
II-M-3
II-M-4
II-H
III-L
III-M
III-H
IV-L
IV-L
IV-M
IV-M-1
IV-M-2
IV-M-3
IV-M-4
IV-H
V-L
V-M-1
V-M-2
V-M-3
V-M-4
V-H
VI-LA
VI-M
Benzene
(mg/kg)
ND
0.22
0.10
0.04
ND
ND
0.10
0.04
0.32
0.10
0.12
ND
0.19
4.8
5.3
13
12
10
9.3
14
14
14
9.5
12
8.1
9.6
22
8.9
11
Lead
(mg/kg)
533
546
668
613
1,650
1,830
2,400
1,470
2,460
1,710
3,170
14,500
2,810
497
477
580
577
588
756
629
583
2,300
2,020
1,690
1,890
2,140
3,140
3,380
3,160
PCBs\mg/kg)
AR1242
1.1
1.4
2.2
2.0
0.6
7.9
7.7
7.8
7.1
26.0
14.0
6.1
9.0
ND
—
2.3
0.6
1.9
1.6
1.2
1.2
12.0
7.0
5.9
7.7
8.4
17.0
13.0
11.0
AR 125-4
ND
1.3
ND
ND
0.4
5.0
3.1
2.9
4.2
21.0
9.8
2.2
4.4
2.3
ND
0.6
1.2
ND
1.3
2.0
3.2
4.4
3.2
8.0
5.1
4.9
7.4
5.8
AR1260
12.0
10.0
18.0
18.0
6.9
19.0
11.0
15.0
13.0
19.0
16.0
7.4
11.0
11.0
—
12.0
5.6
14.0
13.0
14.0
9.0
23.0
12.0
10.0
12.0
16.0
12.0
14.0
12.0
PAHs"
(mg/kg)
27.5
15.7
2.1
27.9
142
11.7
3.3
17.2
4.5
11.5
9.8
29.1
37.5
88.2
134
72.8
64.2
72.9
134
221
134
72.6
97.4
93.2
130
101
62.5
80.9
163
103
-------
Table C-l-7. STC Raw Waste Analytical Results (continued)
Sample
VI-H
VII-L
VII-M
VII-H
VIII-L
VIII-M
VIII-H
IX-L
IX-M
IX-H
IX-HA
BLANK-M
DL
Benzene
(mg/kg)
9.8
22
27
24
21
17
19
20
15
16
30
ND
0.025-0.03
Lead
(mg/kg)
4,140
459
507
687
1,730
2,170
1,700
2,910
3,110
3,070
3,130
ND
4
PCBs"(mg/kg)
AR1242
12.0
0.6
6.0
2.8
12.0
3.6
5.4
9.1
21.0
14.0
18.0
ND
0.02-2.5
AR1254
4.8
1.4
3.7
2.4
4.7
3.0
3.9
6.5
16.0
10.0
10.0
ND
0.02-2.5
AR1260
14.0
6.8
9.5
18.0
15.0
5.5
8.7
8.5
19.0
11.0
17.0
ND
0.02-2.5
PAHs»
(mg/kg)
100
230
18.2
191
173
115
214
254
151
241
202
ND
0.033-9.4
ND
DL
a
b
Not detected
Detection limits
TCMX spike ineffective in matrix, therefore, data were not flagged for low TCMX spike recovery.
Sum of six PAHs. One half detection value used for samples below detection.
104
-------
Table C-l-8. TCLP Analytical Results for STC-Treated Wastes
Sample
I-L
I-MA
I-H
II-L
II-M-1
II-M-2
II-M-3
II-M-4
II-H
III-L
IH-M
III-H
IV-L
IV-M-1A
IV-M-2
IV-M-3
IV-M-4
IV-H
V-L
V-M-1
V-M-2
V-M-3
V-M-4
V-H
VI-LA
VI-M
VI-H
VII- L
VII-M
Benzene
(W5/L)
2.1
2.0
2.0
1.1
1.3
1.6
0.76
1.5
0.96
0.55
0.66
0.79
68
64
28
41
73
88
51
63
49
40
66
10
100
86
28
410
220
Lead
(W5/L)
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
PCBsXlig/L)
AR1242
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AR1254
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AR1260
ND
0.18
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.38
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
PAHs*
(HB/L)
0.08
0.09
0.06
0.07
0.20
0.10
0.12
ND
ND
ND
ND
ND
ND
0.73
0.10
0.63
0.32
ND
0.38
ND
ND
ND
0.41
ND
0.80
0.67
ND
ND
ND
105
-------
Table C-l-8. TCLP for STC-Treated Wastes Analytical Results (continued)
Sample
VII-H
VIII-L
VIII-M
VIII-H
IX-L
IX-M
IX-HA
BLANK-M
DL
Benzene
(W5/L)
140
190
130
170
250
190
210
ND
0.5
Lead
(ug/L)
ND
ND
ND
ND
ND
ND
ND
ND
20
PCBs'(,ig/L)
AR1242
ND
ND
0.19
ND
ND
ND
ND
ND
0.10-0.12
AR1254
ND
ND
ND
ND
ND
ND
ND
ND
0.10-0.12
AR1260
ND
ND
0.24
ND
ND
ND
ND
ND
0.10-0.12
PAHs*
(US/I-)
ND
0.69
2.13
1.85
0.72
0.89
ND
ND
0.01-0.4
ND
DL
a
b
Not detected
Detection limits
TCMX spike ineffective in matrix, therefore, data were not flagged for low TCMX spike recovery.
Sum of six PAHs. One half detection value used for samples below detection.
106
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Case Study C-2
Purity Oil Sales Site
Fresno, California
The Purity Oil Sales (POS) site in Fresno,
California was selected for bench-scale treat-
ability testing to determine the effectiveness of
STC's solidification/stabilization technology on
wastes from this site, and whether the POS site
should be considered for a full-scale STC dem-
onstration under the SITE program.
The POS site is located in Malaga, Califor-
nia, about 1/2-mile southeast of the Fresno city
limits. The site is bounded by South Maple
Avenue to the east, the North Central Irrigation
Canal to the south, and the A.T. and S.F. Rail-
road to the west. The area outside the northern
boundary consists of residential and commercial
properties.
The site is an abandoned oil reprocessing
facility operated mainly for recycling used motor
oils from 1934 until 1975. The steps in the
process involved settling out heavier solids,
dewatering by heating, acidification, and filter-
ing through a clay bed. The wastes produced
during the process included acid sludge, waste-
water, insoluble solids, and spent clay slurry that
were disposed of on site. In addition, storage
tanks existed on site with a nearby impoundment
for collecting spills. Several unlined waste pits
up to 10 feet deep were used during site opera-
tions for storage and disposal of waste materials.
These waste pits were subsequently filled with
soil and demolition debris consisting of concrete,
bricks, steel, wood, and tires. Numerous surface
spills of oily/tarry materials from oil reprocess-
ing also occurred at the site prior to its closure.
Site contamination has resulted from surface
spills, improper disposal practices, and possibly
leaking storage tanks. Contamination attribut-
able to past site activities has been detected in
the ground water (on site and near off site),
canal sediments, and on-site surface and subsur-
face soils. Chemical analyses indicated that the
contaminated waste was acidic, and high in lead
and certain organic compounds. Analytical
results of subsurface boring samples indicated
the waste contained toluene, benzene, polyaro-
matic hydrocarbons (PAHs), methylene chloride,
phthalates, acetone, and other compounds.
Pesticides were also detected in some of the
waste pit areas. The wastes did not meet RCRA
criteria for definition as a characteristic hazard-
ous waste; however, the wastes did have concen-
trations of lead that exceeded the California
Total Threshold Limit Concentration (TTLC)
value for definition as a hazardous waste.
The waste samples were analyzed before and
after treatment by the STC solidification/stabi-
lization processes. The sampling and analyses
were conducted in accordance with a Draft
Preliminary Sampling Plan prepared for EPA's
Office of Research and Development
(U.S. EPA, 1989). The sampling plan detailed
the sampling approach, laboratory procedures,
and quality assurance and quality control proce-
dures for the treatability studies.
EPA's SITE contractor (PRC) collected waste
characterization samples and treatability samples
at the POS site on September 26, 1989. Samples
were obtained from a drum of contaminated
material. The drum was filled with waste col-
lected from soil horizon "B" as part of a removal
action and was selected by the EPA remedial
project manager at the site. Contaminated
material was withdrawn from three different
depths within the drum using a stainless-steel
scoop. The material taken from the drum was
then composited in a 10-gallon drum and split
into several portions. One portion was sent to
STC for treatment, and another portion was
shipped to Engineering-Science, Inc. Berkeley,
California (ESBL), for analysis. ESBL analyzed
109
-------
the raw waste for a number of volatiles, semi-
volatiles, metals, fluorides, asbestos, pesticides,
and polychlorinated biphenyls (PCB). Analytical
methods included a total waste analysis (TWA),
the Toxicity Characteristic Leaching Procedure
(TCLP), and the California Waste Extraction
Test (CALWET).
After obtaining the analytical results from
the raw waste, STC estimated the optimum
reagent-to-waste ratios (by weight) to be used in
the treatability studies, based on experience
from previous testing of similar wastes. STC
then treated the raw waste in four batches. Two
batches were treated at the optimum reagent-to-
waste ratio, one batch was treated at 50 percent
of the optimum ratio, and another batch was
treated at 150 percent of the optimum ratio. The
treated wastes were cured for 28 days and a
portion of each batch shipped to ESBL for
analyses.
ESBL analyzed the treated wastes for the
same set of constituents analyzed in the raw
waste. The TCLP was performed on treated
waste samples representing each of the three
different reagent-to-waste ratios. The results of
these analyses were used to verify the vendor's
estimates for the optimum reagent concentra-
tions.
Upon receiving the analytical results from
the TCLP analyses of the treated waste, STC, in
conjunction with the EPA SITE program manag-
er, selected the reagent-to-waste ratio that would
be used for additional TWA analyses. STC then
sent additional wastes that had been treated at
their chosen reagent-to-waste ratios to ESBL for
analysis. Analytical methods included TWA and
TCLP. These additional tests involved the same
set of constituents analyzed in the previous tests.
The following discussion provides an inter-
pretation of the analytical results from the
testing performed on the raw waste and wastes
treated by STC's solidification/stabilization
process. The TCLP results were evaluated by
calculating the percent reduction of organic and
inorganic constituents that were achieved by the
treatment process. The percent reduction was
calculated by using an "additives ratio" for the
treatment. The additives ratio is defined as the
ratio of all reagents or cements added during
treatment (not including water) to the amount of
waste being treated. The additives ratio was
used to calculate the percent reduction for
organic and inorganic constituents using the
following formula:
Percent Reduction - [l - (1 + Additives Ratio) X Concentration of Treated Waste}
Concentration of Raw Waste J
Table C-2-1 presents the results of TCLP
analyses of raw waste and waste treated by STC
at three reagent-to-waste ratios (0.22, 0.42, and
0.62), plus TWA at the optimum reagent-to-
waste ratio of 0.42. The table shows that the
STC treatment process reduced the leachability
of several constituents, including trichloroethyl-
ene, benzene, and five metals. No measures
were taken to capture and quantify volatiles that
may have been lost due to mixing and curing.
The results shown in Table C-2-1 are gener-
ally consistent across the different reagent-to-
waste ratios for the treated waste and the dupli-
cate analyses conducted on the samples of wastes
treated at the optimum reagent-to-waste ratio.
However, several constituents were associated
with inconsistent trends (both positive and
negative percent reductions) between the differ-
ent treated wastes. These constituents included
lead, toluene, and xylene.
Table C-2-1 also presents the results of total
waste analysis for selected contaminants in the
raw wastes and wastes treated by STC at the
optimum reagent-to-waste ratio of 0.42 as
determined by the TCLP analyses. The table
shows that the STC process reduced the concen-
trations of some of the contaminants including
cadmium, chromium, copper, lead, and zinc.
Lower percent reductions were reported for
benzene and trichloroethylene, and inconsistent
percent reductions resulted for toluene and
xylene.
110
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Based on TCLP analyses, STC's technology
yielded reductions in leachate concentrations for
two of eleven volatile organics. The results for
eight volatile organics were inconclusive due to
low concentrations in the raw waste leachate, or
inconsistent results for reagent ratios. STC's
immobilization technology yielded reductions in
leachate concentrations for three of six semi-
volatile organics; three semivolatiles appeared to
be mobilized by the STC process. STC's tech-
nology yielded reductions in total waste concen-
trations for two of four volatile organics. Two
volatile organics appeared to show an increase in
concentration from the raw waste to the treated
waste after accounting for treatment reagent
dilution. STC's technology yielded reductions in
leachate concentrations for ten of twelve metals.
In conclusion, based on the raw waste and
treated waste leachate concentrations as mea-
sured by the TCLP and percent reductions
obtained through treatment, the STC process
appeared to be more effective in stabilizing
inorganic than organic constituents in the waste
found at the Purity Oil Sales site.
114
-------
Case Study C-3
Kaiser Steel Corporation
Fontana, California
The Kaiser Steel Corporation (KSC) facility
was the site of preliminary treatability testing of
STC's immobilization technology under the SITE
program. The KSC facility at one time occupied
approximately 2,000 acres of land in San Berna-
dino County, California, 45 miles east of Los
Angeles, near the City of Fontana.
KSC opened a fully integrated steel produc-
ing, finishing, and fabricating facility in 1942.
Operations at the plant included steel production
in blast furnaces and basic oxygen furnaces, steel
finishing in a hot strip mill, a plate mill, a cold
rolling mill and a galvanizing mill, and ancillary
facilities such as coke oven batteries. In late
1982, Cuyahoga Wrecking Corporation pur-
chased a portion of the facility for dismantling,
consisting of three blast furnaces, seven coke
oven batteries, and the by-product plant. The
remainder of the plant remained in operation
until 1983. In 1984, California Steel Industries,
Inc. (CSI) purchased the hot strip mill, plate
mill, cold rolling mill, and sheet galvanizing mill
and resumed steel finishing.
Throughout KSC's history a variety of wastes
have been generated at the site, many of which
were placed in a series of on-site disposal areas.
The specific areas of interest for the treatability
study were the tar pits, the east slag pile, and the
gas washer water sludge pits. The three tar pits
were located on the northwest side of the site
and contained 850,000 cubic feet of waste tar
from the coke ovens (listed K087). KSC discon-
tinued use of the tar pits in 1973. Analysis of
the tar pits indicated the waste contained leach-
able naphthalenes and phenols, plus other organ-
ic compounds. The east slag pile was one of two
slag piles located on the southwest side of the
plant. In addition to slag, the east slag pile
reportedly received asbestos from plant demoli-
tion, oily mill scale, waste oil, oily animal fat
sludge, lime-neutralized waste pickle liquor, and
blast furnace gas washer water sludge. Analysis
of oily animal fat sludge in the slag pile indicat-
ed the waste contained teachable nickel and
cobalt. The gas washer water sludge area, locat-
ed in the northeast quadrant, contained three in-
ground pits. Analysis indicated the waste con-
tained leachable lead and cadmium.
Generally, concentrated contaminants were
present as nonaqueous substances that were
predominantly polynuclear aromatic hydrocar-
bons (PAH). Other hazardous constituents
present at the site included benzene, toluene,
xylene, styrene, phenols, naphthalene, dibenzo-
furan, methylene chloride, and chloroform. In
addition, metals such as lead, arsenic, cadmium,
aluminum, iron, chromium, and zinc were
present.
In July 1989, area waste characterization
samples from six on-site locations were collected
and analyzed by EPA's SITE contractor (PRC) to
determine the level of contamination. The areas
studied were the tar pit (TP), slag/animal fat
(SAP), gas washer water sludge (WS), east slag
(ES), slag gas washer sludge (SWS), and by-
product (BP) areas. The samples were analyzed
by Engineering-Science, Inc., using total waste
analysis (TWA), Toxicity Characteristic Leaching
Procedure (TCLP), and California Wet Extrac-
tion Test (CALWET) procedures.
Table C-3-1 summarizes the results of
solidification/stabilization treatability studies on
the contaminated soils and sludges from the
Kaiser Steel Corporation site. The results are
accompanied by the appropriate reporting limits,
additive ratios, and where possible the calculated
percent reduction. The additives ratio was
115
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fi^
n u n n n
J3
-------
derived using all types of reagents, surfactants,
or cements added during treatment but does not
include any added water. Percent reduction was
calculated using the following formula:
Percent Reduction = fl - (1 + Additives Ratio) x Concentration of Seated Waste
Concentration of Raw Waste
In cases where a contaminant value was not
detected in the treated waste, the reporting limit
for the treated waste was used to calculate a
minimum value for percent reduction (indicated
by a ">"). However, if in the raw waste a con-
taminant value was not detected, or not ana-
lyzed, the percent reduction was not calculable
(NC).
The metal that was detected at highest level
by TWA in the raw waste was lead. Lead is
present at a level of 21,200 ppm in raw waste
from the wash-water sludge (WS). Metals were
also present at significant levels in raw waste
from the SAP area. The levels of metals in the
leachate from the raw waste from WS, as
indicated by the TCLP results, were exceeded by
two of the eight regulated metals (cadmium and
lead). This sample also exceeded the CALWET
soluble threshold limit concentrations (STLC) for
both lead and cadmium and therefore meets the
California's hazardous waste criteria.
Base neutral and acid extractable organic
compounds, as indicated by the TWA results,
were detected in concentrations in excess of
10,000 mg/kg in the raw waste samples from the
TP location. Most significant amount of leach-
able organics were also from the raw waste from
the tar pit location with several compounds
having concentration greater than 1 mg/L.
Moderate levels of both organics and metals
have been detected in raw waste from the SAP
area. Arsenic, cadmium, chromium, cobalt,
copper, lead, nickel, naphthalenes, and phenols
are present at moderate levels in the SAP area.
The CALWET test did not indicate that STLCs
were exceeded for any of the metals in raw
waste from the SAP area.
No pesticides, polychlorinated biphenyls
(PCB), or asbestos were detected in any of the
raw waste samples. Therefore, these parameters
were not analyzed for treatability testing.
The raw waste samples were analyzed for the
CALWET list metals. Organics were not
analyzed according to the CALWET protocol
because no organic compounds were detected in
the TWA at concentrations greater than the
respective STLCs. All CALWET inorganic
concentrations, with the exception of the BP lead
and zinc leachate concentrations, were signifi-
cantly higher than the comparable raw waste
TCLP leachate concentrations — in many cases
one or two orders of magnitude greater. Howev-
er, it should also be noted that the CALWET
analyte detection limits were significantly great-
er than the corresponding TCLP analyte detec-
tion limits, and the CALWET method is a more
aggressive leach test than TCLP as a result of
higher acid concentration, longer leaching time,
and greater buffering capacity than TCLP leach-
ing solution.
Based on total waste and TCLP analyses of
the raw waste collected from the six areas on
July 6, 1989, three specific areas were chosen to
test the STC technology at the bench-scale level.
The three areas that were used for treatability
testing were TP, WS, and SAP. Although wastes
from the BP, ES, and SWS areas were not used
for detailed treatability testing, one solidified
waste mold was cast from each location for
subsequent TCLP analysis.
The treatability testing was conducted in two
successive stages. The first stage consisted of
STC specifying the amount of Soilsorb (its
proprietary reagent) estimated to effectively
stabilize the waste. In order to develop an
"optimum" reagent to waste ratio, STC then cast
three sets of molds for each waste: one set at the
specified Soilsorb concentration, one set at 50
percent of the specified Soilsorb concentration,
and one set at 150 percent of the specified
Soilsorb concentration. For example, for the
SAP waste, STC specified a Soilsorb concentra-
tion of 20 percent of the weight of the waste. In
addition to molds cast with this concentration,
STC also cast molds of treated waste containing
10 percent and 30 percent Soilsorb by weight
126
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before addition to the waste. After curing, one
mold of each Soilsorb concentration was tested
by TCLP for each area. One duplicate mold
containing the originally specified Soilsorb
concentration was also tested.
The second stage of the treatability study
was conducted in November 1989 on samples
TP, WS, and SAP. TWA, CALWET, Unconfined
Compressive Strength (UCS), and permeability
tests were made on these samples. TWA and
CALWET results are included in Table C-3-1.
Results for the UCS and permeability tests are
shown in Table C-3-2.
Results from the second-stage treatability
study showed moderate to high percent reduc-
tions for the metals arsenic, cadmium, chro-
mium, lead, and nickel using CALWET leach
criteria; however, arsenic and chromium did not
show consistent percent reductions. TWA of
organic volatiles showed a moderate percent
reduction for xylene and higher percent
reductions for benzene and toluene. However,
no methods were used to capture and quantify
any volatiles that may have been airstripped
during treatment.
Semivolatiles report mixed results with
respect to percent reductions depending predom-
inantly on initial concentrations of the raw waste
and the corresponding reporting limits used in
the calculations for non-detected values in the
treated waste. In general, however, concentra-
tions of semivolatiles were substantially lowered
upon treatment.
Table C-3-2. Summary of Physical Analysis of KSC Waste
Sample
TP
WS
SAP
UCS' (psi)
203
46
247
Permeability11 (cm/sec)
6.4 x 10-7
1.8 x 10 5
6.0 x 10'7
a = Unconfined compressive strength - average of three measurements.
b = average of three measurements
127
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Case Study C-4
Brown Battery Breaking Superfund Site
Reading, Pennsylvania
This case study presents the results of a STC
laboratory-scale treatability study performed on
soils from the Brown Battery Breaking
Superfund site located near the town of Reading,
Pennsylvania. STC's analytical and leach test
results for lead are shown in Tables C-4-1 and
C-4-2. The samples were treated with STC
proprietary reagents and allowed to cure for 7
days prior to teachability analysis. Total lead
concentrations for the untreated waste ranged
from 2,350 ppm to 53,600 ppm. Raw waste
Extraction Procedure (EP) leachates contained
from 5.6 ppm to 159 ppm lead, whereas post-
treatment EP leachates contained 0.24 ppm to
0.29 ppm. Lead concentrations for the
CALWET leachates of the raw waste samples
ranged from 55 ppm to 679 ppm, while the
treated samples contained 0.65 ppm to 4.23 ppm
lead. ANS 16.1 Leachate Test results produced
less than the detectability limits of 0.2 ppm lead
for each of the 5-day leach periods. Untreated
sample pH ranged from 7.5 to 7.8, and the
treated samples ranged from 9.5 to 11.2.
These results indicate that the STC treatment
process did reduce the concentrations of lead in
various leachates; however, since the dilution
factor was not reported, specific contaminant
percent reduction could not be accurately
determined.
Table C-4-1. Lead Analyses for Untreated Brown Battery Plant Soils
Sample
1
2
3
TWA
(ppm Pb)
2,350
14,700
53,600
EP
(ppm Pb)
5.55
52.3
159
CALWET
(ppm Pb)
5.5
301
679
pH
7.5
7.5
7.8
Table C-4-2. Lead Analyses for Treated Brown Battery Plant Soils
Sample
1
2
3
EP
(ppmPb)
0.235
0.411
0.290
CALWET
(ppm Pb)
1.82
4.23
0.65
ANS 16.1«
(ppm Pb)
<0.2
<0.2
<0.2
PH
9.5
9.8
11.2
a = Values are for each 5-day leach period.
128
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Case Study C-5
Lion Oil Company
£1 Dorado, Arkansas
STC organophilic silicates were used to treat
over 30,000 cubic yards of refinery sludge from
the Lion Oil Refinery in El Dorado, Arkansas.
This case study presents the post-treatment
verification analytical results from Engineering
Research Technology (ERT) laboratory for
TCLP leach tests of selected metals and analysis
for volatile and semivolatile organics. In addi-
tion, solidification results are included for
varying sludge-stabilizer compositions.
Table C-5-1 presents the metal analyses for
the treated sludge TCLP leachate. All metals
shown, with the exception of arsenic and bari-
um, were below the method detection limits.
The arsenic level was only slightly above the
detection limits at 0.0036 ppm, while the barium
concentration was 0.19 ppm. Table C-5-2
presents results for the volatile and semivolatile
organic compounds of the treated sludge. Again,
all organic compounds analyzed were below the
detection limits for the treated wastes; however,
concentrations of metals and organic compounds
for the raw sludge were not available for this
report.
Solidification results for the Lion Oil Refin-
ery sludge are presented in Table C-5-3. Un-
confined compressive strengths were measured
after 2, 4, and 5 days for varying sludge-stabi-
lizer compositions. The greatest strengths were
obtained using approximately 70 to 80 percent
sludge by weight in addition to 7 to 11 percent
Type 3 cement and 1.4 to 2.4 percent STC pro-
prietary Soilsorb reagents. In addition, kiln dust,
natural soil, and backfill material, in quantities
varying from 8 to 21 percent, also increased
solidification strengths for the treated sludge.
129
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Table C-5-1. Analytical Results of Metal Concentrations
from the Lion Oil Refinery Treated Sludge
Analyte
As
Ba
Be
Cd
Co
Cr
Hg
Ni
Pb
Sb
Se
V
TCLf
(ppm)
0.004
0.19
<0.05
<0.05
<0.05
<0.20
<0.003
<0.15
<0.15
<0.30
<0.003
<0.05
130
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Table C-5-2. Analytical Results of Volatile and Semivolatile Organic Compounds
from the Lion Oil Refinery Treated Sludge
Volatile Organic Compounds
Benzene
Carbon disulfide
Chlorobenzene
Chloroform
1 ,2-Dichloroethane
1 ,4-Dioxane
Ethyl benzene
Ethylene dibromide
Methyl ethyl ketone
Styrene
Toluene
Xylene
ppm
<5
<5
<5
<5
<5
<10
<5
<5
<10
<5
<5
<5
Semivolatile Organic
Compounds
Anthracene
Benzo(a)anthracene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Benzo(a)fluoranthene
Bis(2-ethylhexyl) phthalate
Butyl benzyl phthalate
Chrysene
Dibenzo(a,h)acridine
Dibenzo(a,h)anthracene
Dichlorobenzenes
Diethyl phthalate
7,1 2-Dimethylbenz(a)anthracene
Dimethyl phthalate
Di(n)butyl phthalate
Di(n)octyl phthalate
Fluoranthene
Indene
Methyl chrysene
1 -Methyl chrysene
Naphthalene
Phenanthrene
Pyrene
Pyridine
Quinoline
ppm
<20
<20
<20
<20
<20
<20
<20
<20
<100
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<100
131
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Table C-5-3. Solidification Results for the Lion Oil Refinery Sludge
Composition
(wt.%)
SL 81.3
C3 8.1
KD 8.2
SS 2.4
SL 70.0
C3 7.6
NS 21.0
SS 2.0
SL 75.6
C3 7.6
BF 15.2
SS 1.6
SL 73.0
C3 11.0
BF 14.6
SS 1.4
SL 73.5
C3 11.0
BF 14.7
SS 0.8
SL 83.3
C3 8.3
KD 8.4
SL 30.0
NS 0.0
C 70.0
SL 33.3
NS 33.3
C 33.3
SL 40.0
NS 30.0
C 30.0
SL 40.0
NS 25.0
C 35.0
Time (hrs)
14
48
72
>72
Unconfined Compressive Strength (psi)
55
63
29
46
17
17
>49
49
52
52
63
>63
33
55
21
21
NT
NT
NT
NT
>63
>63
35
>62
23
22
NT
NT
NT
NT
118
135
47
>135
34
22
NT
>63
56
>56
132
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Table C-5-3. Solidification Results for the Lion Oil Refinery Sludge (continued)
Composition
(wt,%)
SL 40.0
NS 0.0
C 60.0
SL 50.0
NS 0.0
C 50.0
SL 46.0
NS 27.0
C 27.0
SL 40.0
NS 30.0
C 30.0
SL 46.0
NS 27.0
C 27.0
SL 46.0
NS 27.0
C 27.0
SL 50.0
NS 20.0
C 30.0
SL 50.0
NS 20.0
C 30.0
SL 50.0
KD 50.0
SL 50.0
NS 50.0
SL 40.0
FA 60.0
SL 35.0
NS 50.0
KD 15.0
SL 30.0
NS 50.0
KD 20.0
Time (hrs)
24
48
72
>72
Unconfined Compressive Strength (psi)
49
45
21
24-2
>63
>63
63
63
<14
F
<7
7-10
NT
NT
28
42
NT
NT
NT
NT
<14
F
<10
10-14
NT
NT
NT
NT
NT
NT
NT
NT
<14
F
<10
17-21
NT
NT
NT
NT
NT
NT
NT
NT
F
F
<10
NT
133
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Table C-5-3. Solidification Results for the Lion Oil Refinery Sludge (continued)
Composition
(wt,%)
SL 35.0
NS 50.0
FA 15.0
SL 30.0
NS 50.0
FA 20.0
SL 52.0
NS 26.0
C 22.0
SL 50.0
2 INS 20.0
C 30.0
SL 50.0
2 INS 30.0
C 20.0
SL 50.0
17NS 25.0
C 25.0
SL 55.0
NS 25.0
C 20.0
SL 55.0
NS 20.0
C 25.0
SL 60.0
NS 25.0
C 15.0
SL 60.0
NS 20.0
C 20.0
SL 60.0
NS 15.0
C 25.0
SL 65.0
NS 20.0
C 15.0
Time (hrs)
24
49
72
>72
Unconfined Compressive Strength (psi)
F
F
7-10
3-14
14
14-15
<10
<10
<7
<7
<7
<7
F
F
NT
14-17
17
15
NT
F
F
F
F
F
F
F
NT
NT
NT
NT
NT
F
F
F
F
F
F
F
NT
17-21
17-21
15-17
NT
F
F
F
F
F
134
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Table C-5-3. Solidification Results for the Lion Oil Refinery Sludge (continued)
Composition
(wt.%)
SL 65.0
NS 20.0
C 15.0
SL 65.0
NS 15.0
C 20.0
SL 71.4
C3 7.1
NS 21.5
SL 76.9
C3 7.7
BF 15.4
Time (hrs)
24
48
72
>72
Unconf ined Compressive Strength (psi)
<7
<7
F
9
F
F
F
11
F
F
F
13
F
F
F
21
BF - Backfilled Soil
C - Type 1 Cement
C3 - Type 3 Cement
F - Failed upon visual inspection
FA - Fly Ash
KD - Kiln Dust
NS - Natural Soil
NT - Not Tested
SL - Sludge
SS - Soil Sorb
135
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U.S. EPA, 1989. Purity Oil Sales Site, Fresno,
California: Draft Preliminary Sampling Plan.
November.
U S Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, Utn rioor
Chicago, IL 60604-3590
1 36 *u s- GOVERNMENT PRINTING OFFICE: 1993-751-787
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